An Overview of Lithium-Ion Battery Recycling: A Comparison of Brazilian and International Scenarios

Abstract

Purely electric and hybrid vehicles are emerging as the transport sector’s response to meet climate goals, aiming to mitigate global warming. As the adoption of transport electrification increases, the importance of recycling components of the electric propulsion system at the end of their life grows, particularly the battery pack, which significantly contributes to the vehicle’s final cost and generates environmental impacts and CO₂ during production. This work presents an overview of the recycling processes for lithium-ion automotive batteries, emphasizing the developing Brazilian scenario and more established international scenarios. In Brazil, companies and research centers are investing in recycling and using reused cathode material to manufacture new batteries through the hydrometallurgical process. On the international front, pyrometallurgy and physical recycling are being applied, and other methods, such as direct processes and biohydrometallurgy, are also under study. Regardless of the recycling method, the main challenge is scaling prototype processes to meet current and future battery demand, driven by the growth of electric and hybrid vehicles, pursuing both environmental gains through reduced mining and CO₂ emissions and economic viability to make recycling profitable and support global electrification.

1. Introduction

Global sales of electric vehicles (EVs) powered solely by batteries (battery electric vehicles—BEVs) and plug-in hybrids (PHEVs) grew nearly eightfold from 2018 to 2024. Sales increased by 21% between 2023 and 2024. China, Europe, and the United States lead this market, with approximately 60% of BEVs and PHEVs registered in 2024 located in China. In 2023, the total number of BEVs and PHEVs worldwide surpassed 40 million [1]. With the entry of Chinese brands into Brazil, EV sales surged by 140% from 2023 to 2024, according to the Brazilian Electric Vehicle Association (ABVE). At this initial stage, PHEVs are more widely accepted than BEVs, as they can utilize the existing national infrastructure for biofuels, such as ethanol.

The increasing adoption of vehicle electrification is driven by government incentives [2], aimed at achieving climate goals of reducing greenhouse gas (GHG) emissions and global warming. China has announced that GHG emissions will gradually begin to decline in 2030, the United States plans for 50% of new vehicles sold to be zero-emission models by 2030, and in Europe, all vehicles should achieve zero emissions by 2035 [3]. Projections based on existing and developing policies indicate that by 2030, 250 million EVs will be in circulation worldwide, and by 2035, there will be 525 million [1].

The electric propulsion system used in BEVs and PHEVs can be divided into three main components: powertrain, energy storage systems, and integration technologies [4]. The powertrain, which generates the force that moves the vehicle, primarily consists of the electric motor in BEVs, converting electrical energy into mechanical energy. In PHEVs, the electric motor operates in conjunction with a combustion engine. Electric energy storage systems typically take the form of battery packs, where several modules are connected, each composed of a certain number of cells. Within these cells, the conversion of chemical energy into electrical energy occurs [5].

The battery pack represents approximately 40% of the EV’s final cost [6]. However, research shows a downward trend in this cost in recent years, with a notable 14% reduction between 2022 and 2023 [1]. The costs associated with the battery pack are heavily influenced by the prices of the metals used in its production, such as lithium, cobalt, nickel, and manganese [1]. The cathode, which is the most expensive component of the batteries, accounts for more than 50% of the pack’s total cost and is currently manufactured primarily in Asia [6].

Today, lithium-ion batteries are the most commonly used in electric vehicles (EVs) and portable devices such as cell phones and laptops. This is primarily due to several characteristics: the capability to store large amounts of energy in relatively small volumes and the ability to discharge that stored energy quickly, provide high electrical currents, and withstand numerous charge and discharge cycles before their efficiency is compromised [7,8].

The most widely used chemistries in lithium-ion vehicle batteries today are lithium nickel manganese cobalt oxide (NMC) in the European and American markets, such as electric vehicles (EVs) from BMW and Chevrolet, and lithium iron phosphate (LFP) in the Chinese market, including vehicles from BYD [1,9]. LFP chemistry has been gaining ground, with advantages including a 20% lower production cost compared to NMC and generating one-third fewer emissions per kWh during pack manufacture [1]. Currently, LFP batteries are mostly manufactured in China.

The end of the first life of EV batteries occurs when their capacity (Ah) decays to 70–80% of their initial value [7,10,11]. This loss of capacity happens when the active material inside the battery cells becomes inactive due to chemical reactions (side reactions) resulting from charging and discharging over time [11]. Another factor contributing to power loss in the battery is the increase in internal resistance, generated by the growth of the SEI (Solid Electrolyte Interface) [7]. The battery cell operating temperature is another factor that contributes to capacity fade and can lead to a thermal runaway phenomenon. The battery thermal management system is responsible for controlling and keeping the battery pack in a specific temperature range [12,13]. The main mechanisms affecting the Li-ion battery capacity degradation and the estimation of the state of health are reviewed in detail in the references [14,15,16].

The battery manufacturer CATL currently offers an eight-year or 800,000 km warranty for batteries used in light vehicles, according to the company’s website. Vehicle manufacturers like BYD provide an eight-year or 200,000 km warranty, after which the battery’s state of health (SOH) must be at least 70%. At the end of its first life, the battery is no longer suitable for use in vehicles but can be repurposed to store energy from renewable sources, such as wind or solar power, in what is known as its second life. Alternatively, it can be recycled and reused to manufacture new batteries.

Battery recycling is regarded as the final and one of the most critical links in the circular chain of battery value [5]. Given the current trend of growth in EV usage, it is essential to consider a circular production chain to prevent end-of-life batteries from being disposed of improperly in the future, thus avoiding the loss of investment in the extraction and refining of metals that form the cathode, for example, which contradicts the concept of vehicle electrification as a sustainable alternative. In 2023, approximately 80% of battery recycling capacity was based in China [1]. More restrictive legislation is already in effect in Europe, mandating minimum recycling levels for batteries [17].

This paper presents an overview of the current global landscape of automotive lithium-ion battery recycling. Emphasis is placed on the largest international electric vehicle (EV) markets. The recycling processes currently utilized on an industrial scale and in the study phase are discussed, and a comparison is presented between the Brazilian recycling scenario and the international landscape. The objective is to highlight the current Brazilian situation and how this issue is being addressed in other countries, to contribute to the adoption of vehicle electrification in a sustainable manner. The relevance of this work is based on the comparison of the current lithium-ion battery recycling scenario in different countries, discussing the difficulties, challenges, and opportunities. Lastly, this work considers the United Nations Sustainable Development Goals (SDGs), specifically SDG 9 (Industry, Innovation, and Infrastructure) and SDG 12 (Responsible Consumption and Production).

2. Lithium-Ion Batteries

Lithium-ion batteries are utilized in various applications, ranging from electronic devices and cell phones to mobility equipment and electric vehicles [18]. Their usage accounts for approximately 88% of the energy consumption of equipment requiring a battery [19]. Lithium-ion batteries consist of a cathode, an anode, an electrolyte, and a separator [10]. The cathode and anode serve as the two electrodes, with the cathode (+) made of lithium oxide and an aluminum collector, while the anode (−) comprises a copper collector and graphite, a material that can hold lithium atoms between its layers [20]. The electrolyte can be a liquid, gel, ceramic, or polymer made from lithium salts and organic solvents, capable of transporting lithium ions. The separator is constructed from polymers [10,20]. Figure 1 presents a simple structure of a lithium-ion battery.

The operation of a battery in discharge mode is based on the transfer of lithium ions from the anode to the cathode [10]. Lithium ions move through the electrolyte. When they are released from the anode, a charge imbalance is generated, causing the electrons to depart from the anode. Since they cannot pass through the electrolyte, they flow through the external circuit of the battery until they reach the cathode. The movement of electrons due to the charge imbalance generates the electric energy current [20]. This process is reversible through battery charging, where the lithium ions and electrons return to the anode. The separator serves to physically separate the cathode and anode, thereby preventing direct contact between the electrodes.

Among cathode chemistries, lithium cobalt oxide (LiCoO₂—LCO) is the most established for portable electronics due to its high specific capacity and stable cycling performance, although cobalt’s scarcity and cost limit large-scale applications such as electric vehicles [22]. In contrast, lithium manganese oxide (LiMn₂O₄, LMO) allows for high-rate charging and discharging with good thermal stability, although it suffers from a shorter cycle life. Another cathode material option is lithium iron phosphate (LiFePO₄—LFP), which provides excellent thermal stability and safety during overcharge and at high temperatures, making it a reliable choice for stationary energy storage and automotive uses. Further advancements in cathode materials have resulted in more sophisticated chemistries for electric vehicles and high-performance applications [23]. Lithium nickel manganese cobalt oxide (LiNiMnCoO₂, NMC) strikes a balance between high specific energy and low self-discharge, making it widely adopted in the automotive industry. Similarly, lithium nickel cobalt aluminum oxide (LiNiCoAlO₂, NCA) provides high power output and long cycle life, with aluminum enhancing thermal stability and safety [22]. Lithium titanate (Li₄Ti₅O₁₂, LTO) is utilized in applications requiring fast charging, good low-temperature performance, and minimal risk of thermal runaway [24]. In these systems, the anode typically consists of graphite, which has a low cost and enables efficient reversible lithium intercalation. To complement this, Silveira et al. [25] reports that the composition of materials in an LCO battery, by mass, is as follows: LiCoO₂ (32%), metal casing (18%), electrolyte (14%), graphite (14%), copper (8%), aluminum (5%), polymers (5%), polymeric separator (3%), and connector (1%). This diversity of materials highlights the complexity of lithium battery recycling, making it a particularly challenging process.

Overall, the choice of cathode, anode, electrolyte, and separator materials influences the performance, safety, and cost of lithium-based batteries for various applications.

Table 1. Main properties, advantages, disadvantages, and applications of six different lithium-ion battery chemistries [22,26,27,28,29,30].

Cathode Material	Potential (V vs. Li0)	Discharge Capacity (mAh/g at 0.1C)	Specific Energy (Wh/kg)	Capacity Retention, 100 Cycles (%)	Advantages	Disadvantages
LCO (LiCoO2)	3.7–3.9	140	520	97–98	High specific energy	Short service life, Limited load capacity and safety
NCA (LiNiCoAlO2)	3.8	180–200	680–760	93	High energy, High power density, Good service life	High cost, Low security
NMC (LiNiMnCoO2)	3.3	170	560	95	Good performance in all properties	High cost
LMO (LiMn2O4)	3.8	120	455	89–93	High specific power, Safety, Long service life	Average performance across all properties
LFP (LiFePO4)	3.3	155–160	560	>99	Good thermal stability, Excellent safety, Long service life	Moderate specific energy, Low voltage, Reduced performance at low temperature

shows the main properties of each cathode material along with their advantages, disadvantages, and applications.

3. Battery Recycling Processes

Vehicle batteries can be assembled into battery packs for use in electric vehicles following large-scale cell production. Once these packs reach the end of their service life, they may be discarded, sent to recycling facilities for limited reuse, or processed to recover raw materials that can be used in the production of new batteries [31]. With the steady growth in EV production, many questions arise regarding the fate of batteries at the end of a vehicle’s useful life. Improper disposal of batteries has significant environmental impacts, with severe consequences for both the environment and humanity [18]. For example, lead metal is a highly toxic element, and its release into the environment can cause serious health issues. Therefore, it is also important to detect and measure this harmful substance in the environment [32].

In this regard, implementing a recycling process for batteries ensures proper separation, classification, reuse, and disposal of battery components. Recycling offers a suitable destination for batteries while minimizing the scarcity of raw materials and reducing their cost. Battery recycling can significantly reduce environmental impacts compared to traditional lithium production methods. Specifically, the life-cycle GHG emissions for recycled LiOH were 7.8 kgCO₂eq per kg, showing a 37% and 72% decrease compared to virgin LiOH produced from Chilean brine and Australian ore, respectively. Emissions of criteria air pollutants such as NO_x, SO_x, and PM₁₀ can be reduced by up to 84%, and water use was cut by 80% [33].

Recycling processes typically require various types of pretreatments, depending on the materials’ characteristics and the recycling method [21]. To safely start the recycling process and prevent short circuits or spontaneous fires, spent batteries must first be discharged, taken apart manually, and separated before the metal extraction step. Lithium-ion batteries are usually discharged by submerging them in a salt solution [34]. Subsequently, dismantling or mechanical separation involves a sequence of operations designed to safely isolate internal components for further processing. Initially, the plastic shell of the battery is removed, and liquid nitrogen is applied to deactivate hazardous substances such as residual electrolytes [34]. The battery is then secured, and the casing is cut open to access the internal layers. The separated cathode, anode, and separator materials are dried in an oven, usually at 60 °C for 24 h, to remove any residual moisture [35,36]. At this stage, the cathode material stays attached to the aluminum foil by the binder; thus, additional pretreatment steps are necessary to separate them. These steps may include solvent dissolution, ultrasonic-assisted separation, thermal treatment, or mechanical methods [34]. Figure 2 presents a general scheme of the Li-ion battery recycling process. Currently, the main recycling methods for spent lithium-ion batteries (LIBs) include hydrometallurgy, pyrometallurgy, biometallurgy, and direct regeneration [37]. In the following items, we will review some processes used for recycling lithium-ion batteries, presenting the applied methodology, advantages, and disadvantages.

3.1. Pyrometallurgy

The recycling process known as pyrometallurgy uses heat treatments to separate battery materials. Pyrometallurgical metal recovery involves the use of high-temperature furnaces to reduce metal oxides into an alloy primarily composed of cobalt, copper, iron, and nickel [38]. Figure 3 shows a general scheme of the pyrometallurgical recycling process. The pretreatment for this process is straightforward and can be seen in Figure 3 [10,19,21]. This recycling method relies on raising the battery’s temperature in a controlled environment, which prevents the combustion of the materials being separated [10]. In the pyrometallurgy process, the electrolyte is lost through evaporation, and the plastic in the battery separators melts. Materials such as nickel (Ni), cobalt (Co), copper (Cu), iron (Fe), and aluminum (Al) are recovered and can be treated and reused, while silicon (Si), calcium (Ca), magnesium (Mg), and lithium (Li) are lost in the process, along with the slag [19].

Pyrometallurgical recycling of spent lithium-ion batteries (LIBs) begins with a series of thermal pretreatment steps designed to deactivate the cells, safely remove organic compounds, and liberate valuable active materials. The main thermal pretreatments include incineration and pyrolysis. Makuza et al. [40] carefully reviewed all of them in detail. The incineration process is carried out in an oxygen-rich environment, and it is effective for burning off PVDF binders and plastic casings at temperatures typically around 700 °C, improving cobalt and lithium leachability [41]. However, excessive temperatures can lead to the melting of aluminum foils, which hinders cobalt recovery by encapsulating active particles [42]. On the other hand, pyrolysis is conducted in inert or vacuum environments, where organic electrolytes and polymer binders are thermally decomposed without combustion. When the cell is heated in a free-oxygen environment, the decomposition temperature decreases, improving processing efficiency [43]. During pyrolysis, the active cathode material remains as a solid residue suitable for further processing, while volatile compounds are removed by a vacuum system and condensed or collected as gases [44]. Additionally, the aluminum foil becomes brittle, facilitating its separation from the cathode layer [45]. According to the literature, vacuum pyrolysis at 600 °C has demonstrated excellent performance in removing organics while preserving the structure of cathode materials for subsequent recovery. Vacuum pyrolysis has demonstrated >99% Co and Li recovery following leaching of the pyrolyzed residue with H₂SO₄ [45,46]. Another pretreatment is the microwave-assisted pyrolysis, which enhances processing rates and uniformity through internal heating mechanisms that target carbonaceous materials, which are strong microwave absorbers. These thermal treatments also help in battery discharge, enhance safety during mechanical handling, and prevent thermal runaway or gas release [47].

Following pretreatment, extractive pyrometallurgical routes such as roasting and smelting are applied to recover metals. Carbothermic reduction roasting utilizes carbon (from added reductants or residual cell materials) to reduce lithiated metal oxides like LiCoO₂ into metallic Co and Li₂CO₃, typically at 650–1000 °C [48]. A representative reaction pathway for LiCoO₂ is:

4LiCoO₂ + 3C → 2Li₂CO₃ + 4Co + CO₂

(1)

Here, lithium forms water-insoluble Li₂CO₃, while cobalt is reduced to its metallic form. Roasting at 650–1000 °C with controlled carbon dosing achieves high extraction yields: Co and Ni recoveries above 95% have been reported, with lithium recoveries exceeding 98% when salt-assisted roasting is employed [49,50]. Alternative oxidizing or sulfation roasting routes, using H₂SO₄ or Na₂SO₄, can convert lithium into water-soluble Li₂SO₄, enhancing lithium leaching efficiency and minimizing secondary pollution from residual carbon or binders. Salt-assisted roasting is an alternative method that enhances lithium leachability by converting it into more soluble forms, such as Li₂SO₄ or LiNO₃. These methods use additives such as H₂SO₄, Na₂SO₄, or NH₄Cl to produce water-soluble lithium salts and significantly reduce secondary emissions [51]. Microwave-assisted roasting is also emerging as a low-energy, rapid heating approach that preserves product purity while accelerating reaction kinetics [52].

Smelting is the most mature and widely used industrial pyrometallurgical process, which involves directly feeding unsorted, thermally deactivated battery modules into high-temperature furnaces (>1200 °C) without extensive sorting or dismantling [53,54]. Smelting involves two main phases: first, the material is smoothly heated to evaporate the electrolyte and prevent explosions from sudden pressure buildup. Then, it is subjected to high temperatures to melt the remaining feed materials. In this process, metal oxides are reduced and separated into molten alloy (containing Co, Ni, Cu) and slag (containing Li, Mn, Al oxides). Reductants such as carbon and aluminum present in the battery materials facilitate these reductions. While lithium reports mostly to the slag phase, post-smelting slag leaching enables partial recovery. Notably, recovery rates of 94.85% for Li and 79.86% for Mn have been demonstrated using optimized slag chemistry and subsequent leaching [55].

After pretreatment and metal extraction, the recovered materials go through refining processes to separate and purify individual metals. This process typically involves leaching, where metal oxides or alloys are dissolved into aqueous solutions, followed by techniques such as selective precipitation, solvent extraction, ion exchange, or electrowinning to recover metals like cobalt, nickel, manganese, and lithium. In some cases, salting-out methods are used to precipitate specific salts from saturated solutions. The final step often involves cathode regeneration, where purified metal compounds are used to synthesize new active materials through methods such as spray pyrolysis, solid-state reaction, or molten salt synthesis, allowing for the direct reuse of materials in new battery production [30,34,39,56].

Table 2. Pyrometallurgy works with different cathode materials, techniques applied, and process conditions [40,56].

Cathode Material	Methodology	Process Conditions	Efficiency	Refs.
LiNixCoyMnzO2	Roasting	650 °C, 30 min, coke dosage of 10%	Li: 93,67%, Ni: 93,33%, Co: 98.08%, Mn: 98.68%	[49]
Li(NixMnyCo1−x−y)O2	Carbothermal reduction; water leaching	700–1200 °C, 1 h	Li: 93%	[57]
LiNiMnCoO2	Microwave carbothermal reduction; acid leaching	900 °C, 30 min	Li: 99.68%, Co: 97.85%, Ni: 97.65%, Mn: 96.73%	[58]
LiCoNiO2	Smelting	1450 °C, 30 min	Co: 98.83%, Ni: 98.39%, Cu: 93.57%	[59]
Mixed materials	Calcination; organic acid leaching	700 °C, 2 h	Li: 91.5%, Co: 95.02%	[60]
LiFePO4	Salt-assisted roasting (Na2CO3); inorganic acid leaching	600 °C, 2 h	Li: 99.2%	[61]
LiCoO2	Chlorination roasting (NH4Cl); water leaching	400 °C, 20 min	Li: 99.43%, Co: 99.05%	[62]
LiCoO2	Chlorination roasting (NH4Cl); water leaching	350 °C, 20 min	Li: 99.18%, Co: 99.3%	[63]

presents pyrometallurgy results from works that operated with different methodologies and operational conditions.

The advantage of the pyrometallurgical process is its capacity for industrial-scale implementation. It is currently employed in various countries as a solution for recycling lithium-ion batteries [21]. Another benefit of this process is its flexibility in application, as it accommodates different types of batteries with varying physical characteristics (size, weight, and materials used) and electrical properties (voltage, internal resistance, and discharge rate) without requiring significant adjustments to the pyrolysis parameters. Additionally, it is important to highlight that the pretreatment of batteries for pyrometallurgy is less extensive, as it does not necessitate the disassembly and separation of plastic components for the process to occur [10]. Regarding the disadvantages of the pyrometallurgical process in recycling lithium-ion batteries, it is essential to note the emission of harmful gases into the atmosphere, such as CO₂, produced from the combustion of fossil fuels, as well as the high energy demand associated with the process [19].

Several industrial operations have implemented pyrometallurgical technologies on a large scale. Umicore (Belgium) [64,65] employs Ultra-High Temperature (UHT) smelting with integrated off-gas treatment, producing alloy ingots for further hydrometallurgical refinement. Glencore/Xstrata (Switzerland) [64,66] uses a roasting-smelting combination, while Inmetco (USA) [40,64] and Accurec (Germany) [65] apply direct smelting with aluminum and carbon serving as reducing agents. Sony-Sumitomo (Japan) [67,68] has adopted a calcination route to simplify metal separation. Additionally, processes such as EcoBatRec [69] focus on lithium recovery using vacuum carbothermic reduction followed by selective volatilization and condensation. These industrial cases highlight the scalability, robustness, and adaptability of pyrometallurgical pathways, particularly for LIB chemistries rich in cobalt and nickel.

3.2. Hydrometallurgy

Hydrometallurgy is one of the most promising and widely adopted approaches for recovering valuable metals from spent lithium-ion batteries (LIBs), primarily due to its high metal recovery efficiencies and product purities [34]. The hydrometallurgical recycling process involves dissolving battery components in chemical solutions, enabling the extraction of materials for reuse [38]. Figure 4 shows a general scheme of the hydrometallurgical recycling process. To carry out the process, complex pretreatment is necessary, which includes disassembling, crushing, and separating components for optimal application. Additionally, during the pretreatment process, the electrolyte is lost through solvent dissolution, while other materials are sorted and separated. In this step, plastic is separated from metals and sent for recycling [10]. After pretreatment, the leaching process is applied, where the metal compound is chemically attacked. In this process, metals trapped in solid compounds are released through chemical reactions [10]. Then, each of the metals is extracted separately, using different solvents applied to the mixture or by precipitation [18]. The following metals can be extracted with a high degree of purity: nickel (Ni), cobalt (Co), manganese (Mn), copper (Cu), lithium (Li), and aluminum (Al) [10].

The process of hydrometallurgy usually involves leaching metal ions from cathode materials into solution using acidic media, followed by separation and purification steps like solvent extraction, precipitation, or crystallization. Common leaching agents include inorganic acids (HCl, H₂SO₄, HNO₃), organic acids (citric, oxalic, and ascorbic acid), and ammonia-ammonium salt systems (alkaline leaching) [34]. The leaching step is often enhanced with reducing agents such as H₂O₂, sodium bisulfite, or glucose to facilitate the reduction of less soluble metal species (Co³⁺ to Co²⁺) and increase solubility [70,71]

Inorganic acid leaching processes have demonstrated excellent capabilities for metal dissolution. The chemical reaction caused by this process is described below, where “M” represents metals such as Co, Ni, or Mn [72]:

2LiMO₂ + 3H₂SO₄ + H₂O₂ → 2MSO₄ + Li₂SO₄ + 4H₂O + O₂

(2)

Then, each of the metals is extracted separately, using different solvents applied to the mixture or by precipitation [18]. The following metals are extracted with a high degree of purity: nickel (Ni), cobalt (Co), manganese (Mn), copper (Cu), lithium (Li), and aluminum (Al) [10]. Among these, Ni, Co, Mn, and Li are present at levels exceeding 99%, with low impurity content [72]. Another example is the HCl leaching of LiCoO₂, which proceeds via the reaction:

2LiCoO₂ + 8HCl → 2LiCl + 2CoCl₂ + 4H₂O + Cl₂

(3)

with nearly complete dissolution of lithium and cobalt under optimized conditions (4 mol·L⁻¹ HCl, 90 °C, 18 h, 50 g·L⁻¹ solid-to-liquid ratio), although chlorine gas generation poses environmental risks [71]. Alternatively, H₂SO₄ and HNO₃ combined with H₂O₂ as a reducing agent also yield high efficiencies. For instance, Co and Li leaching efficiencies above 99% were obtained with 4 mol·L⁻¹ H₂SO₄ and 10% (v/v) H₂O₂ at 85 °C for 120 min [73]. These conditions promote reactions that enhance dissolution while reducing harmful emissions. Meanwhile, organic acids have gained attention as more environmentally friendly alternatives. Ascorbic acid can act as both a leaching and reducing agent, allowing for the simultaneous dissolution and reduction of Co³⁺. Using 1.25 mol·L⁻¹ ascorbic acid and a 25 g·L⁻¹ solid-to-liquid ratio, leaching efficiencies of 98.5% for lithium and 94.8% for cobalt have been reported [70]. Citric acid, in combination with D-glucose, has also achieved near-complete leaching rates for Li, Ni, Co, and Mn, approaching 99%, 91%, 92%, and 94%, respectively, under mild conditions (80 °C, 120 min) [74].

Table 3. Hydrometallurgy works with different leaching reagents and process conditions [56].

Cathode Material	Leaching Reagents	Process Conditions	Efficiency	Refs.
LiCoO2	HCl (5 M)	95 °C, 70 min, S/L: 10 g/L	Li: 98%, Co: 99%	[75]
LiNixCoᵧMn_zO2	H2SO4 (3 M), FeS2	80 °C, 2 h, S/L: 40 g/L	Li: 99.9%, Co: 99.5%, Mn: 98%, Ni: 98.9%	[76]
LiCoO2	HNO3 (1 M), H2O2 (1.7 vol%)	75 °C, 30 min, S/L: 10–20 g/L	Li: 99%, Co: 99%	[77]
Cathode material	Citric acid (2 M), H2O2 (0.25 M)	80 °C, 2 h, S/L: 20 g/L	Li: 99%, Co: 99%, Mn: 92%, Ni: 90%	[78]
LiNixCoᵧMn_zO2	NH3·H2O (6 M), (NH4)2CO3 (0.5 M), Na2SO3 (0.5 M)	150 °C, 30 min, S/L: 10 g/L	Li: 87.0%, Co: 99.5%, Ni: 91.1%	[79]

presents some hydrometallurgy works that operate under different conditions and leaching reagents.

The advantages of this process include its effectiveness for industrial-scale applications, despite being more time-consuming than pyrometallurgy. It also has a low energy demand during execution and the flexibility to handle different metals by simply changing the chemistry applied to the process [18]. In terms of disadvantages, the effluent generated in the process requires advanced post-processing for purification and safe disposal to protect the environment. Another drawback is the use of chemical reagents, which increase operating costs by accelerating the degradation of instruments and equipment, thereby necessitating a high demand for preventive maintenance. These reagents also require specific care and handling to ensure environmental protection [10,21]. However, some greens are investigated in the literature and could be a more environmentally friendly solution for this type of battery recycling process [80]. Among the main industries employing the hydrometallurgical process for lithium-ion battery recycling are: On To Technology (USA), Euro Dieuze Industries (France), Umicore (Belgium), Dowa Eco-System Co., Ltd. (Japan), Hunan Brunp Recycling Technology Co., Ltd. (China) [19].

3.3. Recycling Processes Under Development

To eliminate or reduce the drawbacks associated with conventional lithium-ion battery recycling methods, new processes are currently under investigation, reaching an acceptable level of maturity at the laboratory stage [21]. Some of these processes are discussed in the following sections.

3.3.1. Direct Process

Direct recycling of lithium-ion batteries involves a laboratory-level process. This process extracts the cathode and anode for reconditioning and reuse in new batteries [21]. During this process, there is no transformation of the original chemical composition of the cathode and anode, only reconditioning occurs, eliminating contaminants and restoring the material [20]. Compared to pyrometallurgy and hydrometallurgy, direct recycling is a more advanced approach that concentrates on restoring the electrodes of spent lithium-ion batteries [81]. This approach offers significant energy savings, reduced use of chemicals, and fewer processing steps compared to pyrometallurgical and hydrometallurgical methods [82]. Recent studies have demonstrated that restored cathode materials can achieve performance levels comparable to pristine materials, with active material recovery often exceeding 95 wt% [83]. Additionally, the process reduces fixed facility costs and reagent consumption while recovering multiple LIB components in forms ready for reuse [84,85].

Like the processes reviewed above, the direct process requires pretreatment for its application, which is collection, classification, discharge, and disassembly of the battery for its subsequent application [21]. After pretreatment, the cathode and anode undergo a purification process in which impurities such as electrolytic salts, carbon, aluminum fragments, and binders are removed. Purification is one of the most important steps in direct recycling, ensuring that residual contaminants and degradation products accumulated during battery operation are removed [86]. The purification process can occur through heating the components or washing them with solvents [87].

For cathodes, impurities such as surface films, metal dissolution residues, and binder residues are removed through a combination of sequential physical and chemical treatments. Studies employ a combination of physical and chemical treatments to separate and purify cathode components before relithiation. Physical separation methods, such as flotation, magnetic separation, and density classification, effectively isolate cathode powders from binder residues and metallic contaminants, thereby minimizing the need for aggressive chemical leaching [88]. Subsequent chemical purification steps may involve weak acid washes or oxidative solutions (for example, H₂O₂) to remove surface impurities without damaging the crystal structure [82]. Following purification, the active material of the components is regenerated by undergoing a re-lithiation process and annealing at 400–900 °C. This process is important to restore the material’s lithium content and crystal structure, as observed in hydrothermal processes used by commercial operations such as OnTo and Retriev [89,90]. Re-lithiation can be solid, involving the addition of solid lithium reagents at high temperatures, or hydrothermal, utilizing a lithium hydroxide solution. For the regeneration of the anode, it may include solvent or thermal treatments to remove solid electrolyte interphase (SEI) layers and conductive additives, followed by structural restoration depending on the extent of degradation [91]. Regarding the yield of direct recycling, current processes under investigation report up to 91% recovery of cathode capacity at the end of the treatment [87].

The advantages of applying the direct process for battery recycling include high energy efficiency, as it consumes minimal energy during execution, and a low environmental impact, with minimal greenhouse gas (GHG) emissions [20]. Despite its advantages, direct recycling faces operational challenges, primarily in the disassembly and classification stages, which currently rely heavily on manual labor due to limited automation and variability in battery chemistry. Additionally, this process lacks robustness because it relies on the integrity of the materials to determine the parameters used at each stage of cathode and anode restoration. Another disadvantage is the difficulty in achieving large-scale material purity that meets industry standards during the purification process [87]. Among the leading laboratories and universities currently researching direct recycling processes are the National Renewable Energy Laboratory (NREL), Argonne National Laboratory, the ReCell Center, and the Energy Innovation Hub [87,91,92].

3.3.2. Biometallurgy

Biometallurgy has emerged as a sustainable and cost-effective alternative for recovering valuable metals from spent lithium-ion batteries (LIBs). This process utilizes leaching to dissolve metals from batteries, a method similar to those employed in hydrometallurgy. Its distinguishing feature is the origin of the acids used, which are generated biologically by bacteria and fungi (bioleaching) [18,19]. For the application of biometallurgy, pre-treatment of the batteries is necessary. This pre-treatment is similar to that used in hydrometallurgy, shown in Figure 4, requiring collection, classification, discharge, comminution, classification, and separation [10]. After pre-treatment, the metals undergo a bioleaching process, where they are chemically attacked by organic acids and released from the solid compounds to which they are chemically bound [10]. Biometallurgy utilizes microorganisms, typically sulfur- or iron-oxidizing bacteria, to generate bio-acids or redox-active species that facilitate the leaching of metal ions from electrode materials [34]. In bioleaching, one of the fungi commonly used is Aspergillus niger, which can achieve a bioleaching rate of 100% for lithium (Li), 94% for copper (Cu), 72% for manganese (Mn), 62% for aluminum (Al), 45% for nickel (Ni), and 38% for cobalt (Co) [21]. This fungus acts efficiently in slightly acidic environments, with a pH between 3.0 and 5.0 [93].

Some studied microbes include Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans, which can produce sulfuric acid and Fe²⁺/Fe³⁺ redox pairs under aerobic conditions. These microbial products enhance the dissolution of metal oxides such as LiCoO₂ through acidolysis or reductive dissolution pathways [94,95,96].

The dissolution mechanism in biometallurgy is specific to the metal and energy sources. For lithium, acid dissolution predominates regardless of the microbial system used, while the leaching of cobalt is more complex. In sulfur-based systems, Co is mainly solubilized through proton attack (acid dissolution), whereas in iron- or mixed sulfur-iron systems, Co dissolution is enhanced by Fe²⁺-mediated reductive mechanisms [34]. Xin et al. [95] studied the bioleaching mechanisms of spent LIBs with mixed cultures of sulfur-oxidizing and iron-oxidizing bacteria under varying energy sources. The results revealed that lithium recovery predominantly occurred via acid dissolution, regardless of the energy source. In contrast, cobalt leaching mechanisms were source-dependent, where in sulfur-based systems, acid dissolution prevailed, whereas in FeS₂-containing systems, Co dissolution involved both acid dissolution and Fe²⁺-catalyzed reduction. Xin et al. [96] investigated various cathode materials, including LiFePO₄, LiMn₂O₄, and LiNixCoyMn_1−x−yO₂, and identified the highest lithium extraction efficiency in the sulfur–Acidithiobacillus thiooxidans system. The results suggest that bio-generated H₂SO₄ was important in Li leaching, while the dissolution of Ni, Co, and Mn was predominantly governed by the mechanism involving Fe²⁺ reduction and acid dissolution.

Despite its eco-friendly nature, the leaching kinetics and pulp densities in biometallurgical processes are still limiting factors. Maximum Co and Li leaching efficiencies of 52% and 80%, respectively, were achieved under optimal conditions, but both decreased significantly when the pulp density increased from 1% to 4% [97]. Strategies to overcome these limitations include optimizing microbial consortia, increasing the bioleaching temperature, or supplementing with catalytic ions. Zeng et al. [98] reported that the addition of 0.75 g·L⁻¹ Cu²⁺ as a redox catalyst in an Acidithiobacillus ferrooxidans culture significantly enhanced the Co leaching efficiency to 99% within 6 days, compared to only 43.1% in the absence of Cu²⁺ after 10 days. Table 1 presents the Biometallurgy process for LIBs recycling. Following bioleaching, biosorption is applied to recover metals from the solution generated. Biosorption has two distinct phases: the first is solid, referred to as the biosorbent, which is composed of plants, bacteria, and fungi, and the second is liquid, containing metal ions [10].

Table 4. Biometallurgy results with different operating conditions and microorganism [39,56].

Microorganism	Type of Material	Conditions	Efficiency	Refs.
A. ferrooxidans	LiCoO2-based spent LIBs	pH 2; 10% (v/v) Modified 9K medium; 100 g/L; 30 °C; 160 rpm; 72 h	Co: 94%, Li: 60%	[99]
Consortium of thermophilic bacteria	Waste LIB cells	pH 1.8; 10% inoculation; 45 °C; 130 rpm	Co: 99.9%, Ni: 99.7%, Li: 84%	[100]
Aspergillus niger	Spent LIBs	26.478 g/L sucrose, 3.45% (v/v) inoculum; pH 5.44	Cu: 100%, Li: 100%, Mn: 77%, Al: 75%, Co: 64%, Ni: 54%	[93]
Acidithiobacillus thiooxidans	LiMnO2 cathode	30 °C, 8 days, S/L ratio: 60 g/L	Li: 93%, Mn: 53%	[101]
Acidithiobacillus ferrooxidans	LiNixCoᵧMnxO2 cathode	30 °C, 72 h, S/L ratio: 100 g/L	Li: 89%, Co: 82%, Mn: 92%, Ni: 90%	[102]
A. caldus & S. thermosulfidooxidans	LiCoO2 cathode	30 °C, 2 days, S/L ratio: 20 g/L	Li: 94%, Co: 95%	[103]
Penicillium	LiCoO2 cathode	25 °C, 30 days	Li: 99.88%, Co: 77.87%	[104]
Aspergillus niger	Mixed cathode materials	30 °C, 30 days, 1% (w/v) pulp density, adapted strain	Li: 100%, Cu: 94%, Mn: 72%, Al: 62%, Ni: 45%, Co: 38%	[105]

summarizes some biometallurgy studies involving different microorganisms and varying operating conditions.

The advantages of this process include a high recovery rate of metals with low energy consumption [18] and minimal environmental impact [21]. However, the lengthy duration required for bacterial growth and the reaction of organic acids on metals, along with the challenges of cultivating the bacteria utilized in the process, are significant considerations. These factors directly affect the difficulty of scaling the process from a laboratory setting to an industrial one [18]. Further research into genetically engineered strains, biofilm reactors, and nutrient recycling could enable more competitive performance. In the context of LIB recycling, biometallurgy holds promise as a complementary or hybrid approach in pre-leaching or selective metal recovery steps within integrated treatment flowsheets.

3.3.3. Comparison of Battery Recycling Processes

Finally,

Table 5. Comparison of recycling methods.

Recycling Processes	Current Scale of Application	Recycling Cost/Time	Advantages	Disadvantages
Pyrometallurgy	Industrial [21].	High/Fast	Application flexibility for different types of batteries [21].	High emission of greenhouse gases in the process [19].
			Simple pre-treatment, without the need for disassembly and separation of materials [10].	High energy demand for process execution [19].
Hydrometallurgy	Industrial [18].	Moderate/Moderate	Application flexibility for different types of batteries [18].	High demand for equipment maintenance, due to degradation caused by chemical reagents used in the process [10,21]
			Low energy demand for process execution [18].	Need for post-treatment of effluents generated in the process, aiming to reduce environmental impact [10,21]
Direct Process	Laboratory [21].	Low/Fast	Low emission of greenhouse gases in the process [20].	Low robustness of the process, with many variables for its execution, depending on the battery to be recycled [87].
			Low energy demand for process execution [20].	Difficulty in obtaining the purity of materials required by the industry [87].
Biometallurgy	Laboratory [18]	Low/Slow	Low emission of greenhouse gases in the process [21].	Long period required to execute the process, due to the time required for the bacteria to react [18].
			Low energy demand for process execution [18].	Low robustness of the process, due to the sensitivity of the bacterial cultivation stage [18].

presents a summary of the recycling methods covered in this study and their advantages and disadvantages. The recycling of lithium-ion batteries (LIBs) can be achieved through several methods, each varying in cost and processing time. Hydrometallurgy is a well-established process that employs acid-based leaching to recover valuable metals. It offers high recovery efficiency but involves the use of hazardous chemicals, requiring careful waste management. Consequently, it is moderately costly and time-consuming due to the multiple leaching, separation, and purification steps involved [106,107]. Pyrometallurgy involves high-temperature processing, enabling fast material recovery. However, it is energy-intensive and has high operational costs. It also results in significant emissions, limiting its environmental viability despite its fast operation [106].

On the other hand, direct recycling presents a promising alternative that retains the structure of cathode materials, allowing them to be regenerated and reused without breaking them down into elemental forms. This method can be considered both cost-effective and energy-efficient, offering faster processing relative to hydrometallurgy. However, it remains in the early stages of industrial development and may face challenges with battery standardization and compatibility [106,108]. Lastly, biometallurgy employs microorganisms to extract metals from battery waste. While this method is highly environmentally friendly and inexpensive due to its minimal chemical usage, it suffers from slow processing times, often requiring days to weeks to achieve substantial recovery, and has yet to be scaled effectively for industrial use [39].

In summary, while pyrometallurgy and hydrometallurgy are currently the most established and scalable methods, direct recycling and biometallurgy represent more sustainable, lower-cost alternatives that require further technological development to reach industrial maturity. According to the literature, conventional methods, such as pyrometallurgy and hydrometallurgy, have a higher environmental impact, with emissions ranging from 67 to 286 kgCO₂eq and energy consumption from 1164 to 4349 MJ/kg of processed material. In contrast, the direct recycling process emits emissions ranging from 21 to 154 kgCO₂eq, and energy consumption varies between 267 and 2251 MJ/kg of LCO cathode processed. Finally, the biometallurgical route demonstrates the most significant reduction in emissions, with reported values between 16 and 19 kgCO₂eq/kg of recovered cobalt, compared to 10 to 158 kgCO₂-eq for other leaching-based methods [56].

Kallitsis et al. [109] performed a life cycle assessment to quantify the environmental impacts and benefits of end-of-life treatment chains for automotive li-ion batteries with NCM cathodes. In the study the authors compared pyrometallurgical and hydrometallurgical recycling routes. The results showed that implementing a circular battery value chain is possible to reduce the environmental burden of battery production by more than 35% in 11 out of 13 environmental impact categories. While both recycling methods reduced overall impacts, hydrometallurgical recycling proved more environmentally advantageous, offering up to 9% greater benefit in categories such as Marine Eutrophication Potential (MEP) due to the selective recovery of lithium as lithium hydroxide and significantly lower energy consumption. In contrast, pyrometallurgical recycling was associated with higher Global Warming Potential (GWP), primarily due to nearly six times higher electricity demand, despite its operational simplicity and scalability. Kallitsis et al. [109] also presented that the recovery of aluminum and copper, mainly from the battery pack casing and busbars, accounted for more than 50% of the environmental benefits in 7 out of 13 impact categories, with aluminum alone contributing to approximately half of the GWP reduction. Furthermore, the recovery of nickel and cobalt from battery cells played a key role in mitigating toxicity, air quality, and resource depletion impacts. The integrated analysis of LIB production and recycling showed significant reductions in Terrestrial Acidification Potential (74%), Metal Depletion Potential (77%), Human Toxicity Potential (50%), and Global Warming Potential (35%). The study also highlighted the influence of geographic specificity, showing that regions with carbon-intensive electricity grids gain the most from recycling interventions.

4. International Recycling Legislation and Scenario

Today, China, Europe, and the United States have the highest growth rates in the EV market, serving as global references in the transition to vehicle electrification. China is a strong leader in this market, with sales rates for both light and heavy vehicles that total the sales of Europe and the United States combined [1]. In addition to standing out as the largest manufacturer of items such as lithium-ion batteries, it utilizes a verticalized production chain, which includes technology from metal extraction and refining to the production of cathodes, cells, and battery packs [110,111]. This verticalized production chain is considered one of the reasons why Chinese electric vehicles reach consumers at lower prices than those of competitors from other countries.

China also stands out as one of the countries with the most advanced regulations for recycling automotive batteries. Although the battery production chain is largely verticalized, the country still relies on the import of some raw materials, such as lithium from Chile and Australia, and cobalt from the Democratic Republic of Congo [112]. Battery recycling and recovery of these imported metals are seen as strategic, not only in terms of climate goals, but also from the perspective of reducing the domestic EV market’s exposure to the price volatility of these raw materials, which tend to become more expensive with increasing global demand.

In 2024, the Ministry of Industry and Information Technology (MIIT) introduced changes to the regulatory project for EV battery recycling, the Specifications for the Comprehensive Utilization of Waste EV Batteries 2024. These changes stipulate new and stricter recycling rates that recycling companies must achieve, including minimum metal recovery rates of 90% for lithium and 98% for nickel, cobalt, and manganese. Additionally, 60% of the material recovered through battery recycling annually must be reused, and at least 3% of the investment allocated for EV battery recycling must be dedicated to research and development in the sector [113]. The so-called “white list” issued in 2019 was also updated, presenting 156 companies that are qualified and certified according to the government’s standards for EV battery recycling [114].

Brunp Recycling, a subsidiary of the battery manufacturer CATL, is on China’s white list. The company employs the hydrometallurgy method to recover over 98% of the cathode material, aiming for a continuous cycle in the production chain [115]. According to the company’s website, the recycling process boasts a recovery rate of 91% for lithium and 99.6% for nickel, cobalt, and manganese. The company has partnerships with vehicle manufacturers, battery producers, and EV maintenance shops, which send discarded batteries directly to the recycling plant.

Although Chinese recycling policies are well developed, significant challenges remain regarding the competitiveness of authorized recycling companies compared to smaller, non-certified recyclers. These smaller operators benefit from lower operating costs but often fail to comply with government-established recycling guidelines and improperly store batteries, which can lead to accidents and environmental harm. Li, Wang, Li, and Jiao [112] note that the automotive battery recycling market in China is still in its early stages, with only 25% of end-of-life batteries recycled by authorized companies. As a solution, there is ongoing debate about how government subsidies can be allocated to both recyclers and consumers to promote the use of proper recycling channels, thereby enhancing their competitiveness by reducing operational costs, for example [112].

The European Union also stands out in the global landscape of EV battery recycling, with legislation that has already been established and was recently revised, aiming to make batteries sustainable throughout their life cycle. This legislation targets goals such as a circular economy and zero pollution during this energy transition period, striving for independence from imported fuels. In 2025, the Battery Directive 2006/66/EC will be repealed and replaced by the new Battery Regulation 2023/1542. This new document reestablishes minimum recycling efficiencies. Starting in 2026, 65% by mass of lithium-ion batteries must be recycled, increasing to 70% by mass in 2031. From 2028, 90% of the cobalt, copper, and nickel initially used must be recovered, while a minimum recovery limit of 50% is set for lithium [17]. These limits apply to both batteries produced within the European Union and those imported.

The new European regulation also states that to maintain the sustainability of the entire life cycle of batteries, requirements for the end-of-life stage need to be established and followed. Government support must be provided to create a battery recycling market and a market for the use of recycled raw materials. Battery producers must assume extended producer responsibility (EPR) for the batteries they have produced throughout their entire life cycle, financing the costs of stages such as collection, treatment, and recycling.

In their study, Seika and Kubli [116] simulated the long-term economic effects of the requirements imposed by the Battery Regulation 2023/1542 in Europe and how the battery market is consolidating. According to them, battery recycling is indeed stimulated by the new regulation through mandatory recycling actions, increasing the demand for recycled materials by requiring producers to use a portion of these materials in the new batteries they produce. As the demand for batteries is projected to grow in the coming years, this will increase the value of materials from recycling, stimulating sector growth. Seika and Kubli [116] point out, however, that the new regulation does not consider the second life of the battery, which disadvantages the sector seeking to reuse or even repair automotive batteries for other applications before recycling. According to the study, if the new regulation were not in effect, battery reuse would be even more economically viable than battery recycling. It would also be supported by the migration of existing battery chemistries to cobalt-free LFP. Finally, they mention that establishing a battery recycling market is urgent, but it should not come at the expense of sacrificing the emerging battery reuse market in the long term. Establishing a minimum lifespan for the battery without defects before the recycling process is highlighted as a solution [116].

The United States lacks specific policies mandating the recycling of lithium-ion automotive batteries [117]. The United States Environmental Protection Agency (EPA) classifies lithium-ion batteries as hazardous materials, and their transportation and storage are regulated under the Hazardous Materials Regulations (HMR), 49 CFR parts 171–180. The agencies advise consumers not to dispose of lithium-ion batteries, such as those used in EVs, in public recycling bins. Instead, they should be returned to the manufacturer or retailer, as these batteries contain materials deemed critical minerals (cobalt, graphite, and lithium), which are economically and strategically significant to the government for producing new batteries. The US Department of Energy (DOE) established the Battery and Critical Mineral Recycling Program, providing financial incentives totaling US$ 125 million (according to BIL 40207 (f)) for research and development of projects that introduce innovations and practical strategies for reusing and recycling batteries. One of the objectives is to foster the growth of a market for recycled materials and critical minerals. In 2022, under the Biden administration, the government offered incentives to automotive manufacturers to utilize recycled minerals, primarily through hydrometallurgical and pyrometallurgical methods, in the production of their batteries, via the Inflation Reduction Act [118].

The American company Li-Cycle, founded in 2016 and publicly listed in 2021, specializes in recycling lithium-ion batteries, recovering critical minerals, and aims to create a closed national cycle for battery production and recycling, according to information on the company’s website. The company collaborates with a network of partners known as Spoke & Hub, where the spokes focus on discharging, dismantling, and crushing the batteries to produce “black mass,” a wet granulated material containing the components that make up the cathode and anode, such as nickel, cobalt, lithium, and graphite [119]. The hubs concentrate on recycling the black mass by extracting and purifying the metals through processes such as hydrometallurgy. The company has already formed partnerships with automotive manufacturers like General Motors, which aim to maximize the use of recycled materials in manufacturing batteries for new EVs [120].

Companies like Redwood Materials are investing not only in recovering critical materials from old batteries but also in utilizing these materials to manufacture new cathodes and anodes, aiming for independence from Asia in the supply of these components. A partnership with Ford, Toyota, and Volkswagen America was announced in 2022, in addition to existing collaborations with Volvo and Panasonic [120]. Ascend Elements is another example of a recycling company, having teamed up with Honda to recycle batteries from Honda and Acura vehicles. Their patented recycling process, called Hydro-to-Cathode, consumes less electrical energy than traditional hydrometallurgical and pyrometallurgical methods. It effectively extracts impurities from the black mass, resulting in critical minerals of the cathode remaining intact and dissolved in an aqueous solution. The metals are then rearranged using microstructure engineering to create new cathodes built according to customer specifications. This technique enables the recycling of old first-generation car batteries, as well as cell phone and notebook batteries, to produce next-generation cathodes [121,122].

Regarding the South Africa scenario, Chigbu et al. [123] performed a recent qualitative study on South Africa’s potential in remanufacturing used electric vehicle lithium-ion batteries through stakeholder interviews and institutional theory. The authors highlight the country’s emerging capabilities in technical expertise, sustainable infrastructure, and regulatory alignment with global standards. It was also proposed a strategic initiative, such as mobile remanufacturing labs and innovation hubs to support workforce development and circular economy integration, positioning South Africa as a potential leader in EV LIB remanufacturing.

5. Brazilian Recycling Legislation and Scenario

In Brazil, vehicle electrification is still in its early stages. EVs imported mainly from China are beginning to show high sales rates, and projections indicate that this trend is likely to continue [1]. It is noteworthy that in Brazil, unlike in other countries, PHEVs are more widely accepted by consumers than BEVs [1]. Several factors contribute to this, including the lack of charging infrastructure, which affects long-distance travel in a country with continental dimensions. Additionally, the Brazilian government offers incentives for using ethanol in conjunction with electric motors, capitalizing on existing technological advancements in biofuels [124]. According to Branco et al. [125], fully electric vehicles in Brazil can reduce greenhouse gas emissions by 85% compared to gasoline-powered cars, but incur a 96% higher cost per kilometer than flex-fuel vehicles. On the other hand, hybrid flex-fuel vehicles running on ethanol can cut emissions by 76%, offering a more cost-effective alternative. In this context, the Brazilian government prefers to encourage the use of biofuels in the transport sector, specifically using biodiesel and ethanol [126,127].

Nevertheless, Brazil lacks a specific policy for recycling lithium-ion batteries, as the volume of automotive batteries of this type reaching the end of their life remains low. The current legislation, comprising Conama Resolution No. 401 of 2008 and Law No. 12,305 of 2010—which establishes the National Policy on Solid Waste—only addresses reverse logistics and the obligations of manufacturers and distributors of lead-acid batteries, according to the website of the Brazilian Institute of the Environment and Renewable Natural Resources (IBAMA). This legislation cannot simply be extended to automotive lithium-ion batteries, as proposed in Law Project 2327/2021, since electric vehicle batteries possess unique characteristics in several areas, such as special care in transportation, storage, and discharge, recycling methodology, and products generated by the process. It is essential to create specific legislation, as seen in other countries mentioned above, outlining the obligations of battery manufacturers and importers, and fostering the development of a sustainable recycling economic chain.

In December 2023, the federal government established the National Green Mobility and Innovation Program (Mover) to align the country with global carbon emission reduction goals. In 2024, the program was enacted as Law nº. 14,902/2024. This law allows for a 2% reduction in the Tax on Industrialized Products (IPI) for vehicles that meet recyclability standards starting in 2025. By 2027, a 3% tax reduction is also set for light commercial hybrid vehicles that exclusively use ethanol engines. Additionally, incentives totaling R$19.3 billion by 2028 are provided for conducting national research and development activities in the mobility sector [128].

However, with the Tax Reform enacted in 2023, Brazilian taxes will be changed, with the creation of the Selective Tax (IS), which will partially replace the IPI. The IS seeks to discourage the consumption of products considered harmful to health and the environment. In 2024, the Complementary Law Project PLP 68/2024 presented by the Executive Branch generated discussions due to controversy when proposing changes to the IS, excluding trucks from taxation due to their importance in the production chain, but including EVs due to the pollution generated by the disposal of batteries, demonstrating the government’s lack of knowledge regarding aspects of recycling existing in the country [124].

There are companies focused on recycling lithium-ion batteries in Brazil. These companies aim to strengthen their strategic position in the current landscape, but they note that Brazilian regulations could facilitate this process by promoting a reduction in the tax burden, which remains very high for this sector. Another issue is that regulations must address unfair competition created by the existing parallel market that collects used batteries and exports them irregularly, without paying taxes [129]. According to ABVE, the main companies specializing in recycling lithium-ion batteries operating in Brazil in 2024 are Re-Trek, Energy Source, and Lorene. These companies recycle batteries from cell phones, laptops, tablets, and more.

Energy Source was founded in 2016 and focuses on repairing batteries for their second life, as well as recycling batteries at the end of their life. The company produces black mass at the end of the first stage of recycling and can extract metals such as cobalt, lithium, nickel, and manganese from it by applying a hydrometallurgical solution, according to the company’s website. Re-Teck Brasil, founded in 2000, is an American multinational company that specializes in disassembling and characterizing battery cells in Brazil. The material is then sent to the United States, where black mass is generated, and rare metals are extracted from it. The company plans to install a national plant to process battery materials in the future [124]. Lorene was founded in 1997 and focuses on the purchase and proper disposal of materials containing precious metals in their composition, such as catalysts, activated carbon, and lithium-ion batteries for electronics and automobiles. In the battery recycling process, the company produces black mass and extracts rare metals from it through thermal processes, according to the company’s website.

Another company worth mentioning is Tupy, a Brazilian multinational founded in 1938 that specializes in producing structural components from cast iron. The company has invested in research and development focused on recycling lithium-ion batteries, partnering with educational institutions such as Senai of Electrochemical Innovation [124]. A study conducted with Tupy demonstrates how automotive lithium-ion batteries were recycled through a hydrometallurgical process with an efficiency exceeding 90%. The recovered metals were used to manufacture new cathodes, which were assembled into new cells that, upon testing, exhibited performance similar to that of cells produced using metals sourced from mining. The cells made from recycled metals were classified as suitable for use in vehicle applications [130].

The current scenario of vehicle electrification brings both challenges and opportunities. Brazil has a large territorial area, which requires logistical planning to collect batteries in the country’s interior and then direct them to recycling points located in major urban centers, while adhering to economic and environmental guidelines throughout the process. This challenge has already been addressed in the lead-acid battery recycling chain, which is already well-established and can serve as a reference. The country is mainly interconnected by highways, with heavy transport vehicles being the main form of transport of industrial and agricultural goods between regions, 99% of which use diesel as fuel [124]. There are opportunities for the development of vehicle electrification of transport fleets, which in 2023, considering also passenger cars, were responsible for 44% of the country’s GHG emissions from the energy and industrial sectors [131].

Although the country has considerable reserves of essential metals such as lithium, nickel, and manganese, the process of recycling batteries to recover these materials is cheaper than mining and refining these metals [129], emphasizing the importance of applying good, efficient, and well-planned recycling methods according to the specific needs of the Brazilian scenario.

Table 6. Comparison of Brazilian and international recycling scenarios. Data collected from [1,17,113].

Country/ Region	Number of EVs (BEVs + PHEVs) on the Road in 2024	Lithium-Ion Batteries Recycling Legislation	Minimum Material Recovery Targets Stipulated	Examples of Recycling Industries	Average Material Recovery Rate on Industries
China	34.00 million	Specifications for the Comprehensive Utilization of Waste EV Batteries 2024 (MIIT)	90% for lithium; 98% for nickel, cobalt and manganese.	Huayou Cobalt; Brunp Recycling; GEM; GHTECH.	92% for lithium; 98% for nickel, cobalt and manganese; 89% for copper.
European Union	10.20 million	Battery Regulation 2023/1542	50% for lithium; 90% for cobalt, copper, lead and nickel.	Hydrovolt (NO); Altilium (UK); Librec (CH).	94% for lithium, nickel, cobalt and manganese and copper.
United States	6.30 million	-	-	Redwood Materials; Ascend Elements; Cirba Solutions; Cox Automotive.	95% for lithium, nickel, cobalt and manganese and copper.
Brazil	214,000	-	-	Energy Source; Lorene; Tupy.	90% for lithium, nickel, cobalt and manganese and copper.

provides a summary comparing the international and Brazilian scenarios described earlier. It includes examples of recycling companies from each country or region, along with the average rare metal recovery rate calculated using data provided by these companies.

6. Conclusions

Based on the bibliographic review, the importance and relevance of battery recycling for reducing the environmental impacts of greenhouse gas (GHG) emissions compared to traditional lithium production methods is clear. It is also important to highlight that conventional lithium-ion battery recycling techniques, such as pyrometallurgical and hydrometallurgical processes, are currently the most widely used by recycling companies worldwide. These methods have demonstrated effectiveness on an industrial scale, mainly due to their flexibility in processing various battery chemistries and their rapid processing times. However, pyrometallurgy is an energy-intensive process that operates at high temperatures, resulting in significant emissions and high operational costs. Although hydrometallurgy has a lower environmental impact compared to pyrometallurgy, it involves hazardous chemicals, requiring strict waste management practices and leading to a moderate overall environmental impact.

On the other hand, direct recycling and biometallurgy could be more sustainable and have lower operational costs. However, their processing times are still longer than those of pyrometallurgy and hydrometallurgy. Additionally, direct recycling heavily depends on the specific battery type being processed, which makes scaling difficult, while biometallurgy is limited by the sensitivity of the bacterial cultivation stage. These factors currently restrict the industrial use of both methods, requiring further development to make large-scale implementation financially viable.

It is worth remembering, however, that even in countries like China, where vehicle electrification is advanced and automotive battery recycling is a reality, the recycling stage is still considered to be in its initial phase of implementation. The recycling technologies used can still be evolved, and alternative methods may be developed to enhance current practices. In countries like Brazil, where automotive lithium-ion battery recycling is still in the planning phase, it is noteworthy that the most efficient alternative recycling methods are considered from the outset to promote energy savings and waste reduction at this stage of the battery life cycle.

It is crucial to consider the battery recycling stage from the moment the product is designed, aiming to facilitate the final stage of dismantling and reusing the materials used. The closed life cycle vision of the battery must be considered by manufacturers and users, reinforcing the concept of EVs as a sustainable solution. With the increase in global demand for specific metals used in the manufacture of cathodes, for example, it is likely that a shortage of these resources will be experienced in the coming years.

The recycling of automotive batteries requires government incentives to ensure it is carried out properly, following established standards, and stimulating a regulated and economically viable recycling market. The consumption of recycled materials in the manufacture of new batteries must be encouraged, creating a circular production chain. Countries must develop specific and well-planned legislation, using existing successful policies in other nations as a reference. The consumer should also be the focus of government policies, promoting recycling through the proper channels rather than an unregulated parallel market.

In Brazil, the demand for recycling automotive lithium-ion batteries remains a future prospect. The country is currently experiencing an influx of EVs, particularly from China. It is crucial to prepare the nation for the upcoming need to dispose of batteries reaching their end-of-life, which is expected to occur in the next eight to ten years. Retaining the “rare metals” from these batteries in Brazil and reintegrating them into the national production of new cathodes is a strategy that would enhance the industrial chain. Brazil is notable for its large reserves of strategic materials relevant to electrification; however, it lacks the developed technology to convert these raw materials into finished products. Government incentives for the adoption of BEVs and PHEVs, foreign investment in domestic production, and partnerships with major EV manufacturers could assist Brazil in developing essential technologies and distinguishing itself in the current electrification landscape.

Sustainability in the cargo transportation industry can serve as a strong differentiator for companies using electric trucks, and it can be a value that clients appreciate and that justifies the initial investment. To make this successful, the national charging infrastructure must be built, and government incentives for purchasing electric trucks, which are often more costly, would also support this effort.

It is essential that during the recycling stage, authorized channels are used, eliminating the parallel market that exports used batteries solely for profit, disregarding the consequences. Producers and importers must be responsible for the batteries they produce until the end of their life, covering the costs incurred during recycling and reinforcing the concept of a circular production chain. Finally, government incentives such as tax reductions on domestically manufactured and imported products can help keep the regulated sector more competitive and attractive to consumers than illegal alternatives.