Search Results (39)

In this work, graphite anodes and lithium iron phosphate (LFP) cathodes are used to examine the effects of sodium hexafluorophosphate (NaPF₆) and potassium hexafluorophosphate (KPF₆) electrolyte additives on the formation of the solid electrolyte interphase and the performance of lithium-ion batteries in both half-cell and full-cell designs. The objective is to assess whether these additives may increase cycle performance, decrease irreversible capacity loss, and improve interfacial stability. Compared to the control electrolyte (1.22 M Lithium hexafluorophosphate (LiPF₆)), cells with NaPF₆ and KPF₆ additives produced less SEI products, which decreased irreversible capacity loss and enhanced initial coulombic efficiency. Following the formation of the solid electrolyte interphase, the specific capacity of the control cell was 607 mA·h/g, with 177 mA·h/g irreversible capacity loss. In contrast, irreversible capacity loss was reduced by 38.98% and 37.85% in cells containing KPF₆ and NaPF₆ additives, respectively. In full cell cycling, a considerable improvement in capacity retention was achieved by adding NaPF₆ and KPF₆. The electrolyte, including NaPF₆, maintained 67.39% greater capacity than the LiPF₆ baseline after 20 cycles, whereas the electrolyte with KPF₆ demonstrated a 30.43% improvement, indicating the positive impacts of these additions. X-ray photoelectron spectroscopy verified that sodium (Na⁺) and potassium (K⁺) ions were present in the SEI of samples containing NaPF₆ and KPF₆. While K⁺ did not intercalate in LFP, cyclic voltammetry confirmed that Na⁺ intercalated into LFP with negligible impact on the energy storage of full cells. These findings demonstrate that NaPF₆ and KPF₆ are suitable additions for enhancing lithium-ion battery performance in the popular artificial graphite/LFP system. Full article

In this study, the lithium-ion (Li-ion) battery type, which has a high-power density and utilizes lithium as the primary conductive terminal, has been employed. Within the scope of this research, a one-dimensional isothermal Li-ion battery model has been investigated under various electrolyte (both liquid and solid) and electrode materials using the COMSOL Multiphysics software. The obtained simulation results have been corroborated with information sourced from the literature and establish a foundational framework for future studies. The average range of electrolyte salt concentration in battery components is slightly higher for batteries utilizing polymer electrolytes compared to those with liquid electrolytes. During discharge at five different C-rates, Li-ion batteries with liquid electrolytes displayed higher voltage than those with polymer electrolytes. On the other hand, the one with the lithium iron phosphate (LFP) positive electrode exhibits the greatest variation in lithium concentration at the surface of the positive electrode at the end of discharge. Conversely, the battery using a LiNiO₂ cathode shows the smallest surface lithium concentration variation during the same period. This pattern is similarly observed for the lithium concentration at the center of the electrode particles. The presented model can be used to explore innovative electrolyte and electrode materials to improve the design of Li-ion batteries. Full article

The rapid growth of lithium iron phosphate (LiFePO₄, LFP)-based lithium-ion batteries in energy storage raises urgent challenges for resource recovery and environmental protection. In this study, we propose a novel method for rapid and selective lithium extraction and the resynthesis of cathodes from spent LFP batteries, aiming to achieve an economically feasible and efficient recycling process. In this process, a selective leaching H₂SO₄-H₂O₂ system is employed to rapidly and selectively extract lithium, achieving a leaching efficiency of 98.72% within just 10 min. Through an exploration of the precipitation conditions of the lithium-containing solution, high-purity Li₂CO₃ is successfully obtained. The recovered FePO₄ and Li₂CO₃ are then used to resynthesize LFP cathode materials through a carbon-thermal reduction method. A preliminary economic analysis reveals that the disposal cost of spent LFP batteries is approximately USD 2.63 per kilogram, while the value of regenerated LFP reaches USD 4.46, highlighting the economic advantages of this process. Furthermore, with an acid-to-lithium molar ratio of only 0.57—just slightly above the stoichiometric 0.5—the process requires minimal acid usage, offering clear environmental benefits. Overall, this work presents a green, efficient, and economically viable strategy for recycling spent LFP batteries, showcasing strong potential for industrial application and contributing significantly to the development of a circular lithium battery economy. Full article

The recycling of lithium iron phosphate (LiFePO₄) batteries from electric and hybrid vehicles was investigated, by applying mechanical pretreatment and hydrometallurgical methods. The aim was to extract lithium (Li) into the aqueous solution and precipitate iron (Fe) in the form of ferric iron phosphate (FePO₄). Samples of lithium iron phosphate (LFP) batteries from small electric vehicles provided by the company BEEV were used in this study. Initially, the black mass was isolated using mechanical crushing, screening, and sink–float separation methods, avoiding the need for costly chemical or thermal treatments. The cathodic material was then leached with sulfuric acid (H₂SO₄) and hydrogen peroxide (H₂O₂) to oxidize ferrous to ferric iron, resulting in the precipitation of iron phosphate, which was collected in the solid residue from the leaching process. Leaching tests were conducted by varying the concentrations of sulfuric acid and hydrogen peroxide, as well as the leaching time. It has been indicated that by using a sulfuric acid concentration equal to the stoichiometric requirement, and hydrogen peroxide at four times the stoichiometric amount, Li extraction of greater than 98% was achieved within the first few minutes of leaching, while iron extraction remained below 0.5%. Full article

Lithium-ion batteries that use lithium iron phosphate (LiFePO₄) as the cathode material and carbon (graphite or MCMB) as the anode have gained significant attention due to their cost-effectiveness, low environmental impact, and strong safety profile. These advantages make them suitable for a wide range of applications including electric vehicles, stationary energy storage, and backup power systems. However, their adoption is hindered by a critical challenge: capacity degradation at elevated temperatures. This review systematically summarizes the corresponding modification strategies including surface modification of the anode and cathode as well as modification of the electrolyte, separator, binder, and collector. We further discuss the control of the charge state, early warning prevention, control of thermal runaway, and the rational application of ML and DFT to enhance the LFP/C high temperature cycling stability. Finally, in light of the current research challenges, promising research directions are presented, aiming at enhancing their performance and stability in such harsh thermal environments. Full article

Cathodes undergo unavoidable lithium loss due to the formation of a solid electrolyte interface (SEI), which seriously affects the energy density of lithium iron phosphate (LFP) batteries. To compensate for the initial capacity loss, we introduced an NiCo-Li₂Se nanocomposite to an LFP battery system to act as a competitive cathode prelithiation additive. Benefiting from its zero gas-emissions, ambient stability, high irreversible capacity, low delithiation potential, and good compatibility with carbonate-based electrolytes, the NiCo-Li₂Se additive based on the chemical conversion reaction effectively offset the initial lithium loss. As a result, with 10 wt% addition, the initial charge capacity of the Li||LFP half-cell was improved by 34 mA h g⁻¹. The Gra||LFP-Li₂Se full-cell released an initial discharge specific capacity of 159.7 mA h g⁻¹, which increased by 18% compared with the Gra||LFP full-cell, resulting in improved cycling stability. In addition, COMSOL Multiphysics simulation was applied to verify the function of the NiCo-Li₂Se additive, and pouch cells were assembled to explore its potential in large-scale industrial application. This work provides a meaningful research direction for the design of a prelithiation additive for LFP cells. Full article

This study investigates the design and geometric properties of high-power and low-temperature 18650 and 26650 lithium iron phosphate (LFP) cells. The analysis focuses on the geometry and components’ thicknesses and deriving CAD models for both cell formats. Design variations were observed, even within cells from the same manufacturer. For instance, one manufacturer’s 26650 cell was not a scaled-up version of their 18650 cell, and no equivalence was found between the designs of high-power and low-temperature cells from the same manufacturer. Thus, modifications are not purely chemistry based. The results also reveal deviations from the literature values for jelly roll component thicknesses, with anode current collectors averaging 61 µm and cathode current collectors averaging 60 µm. Coating thicknesses varied, with anode coatings averaging 32 µm and cathode coatings averaging 52 µm. These variations in current collector and coating thicknesses suggest that both high-power and low-temperature LFP cell designs differ from the typical literature values. Furthermore, a trade-off was observed between low-temperature operation with two-tab designs and high pulse capability with limited minimum operating temperatures. Additionally, smaller particle sizes in anode coatings were associated with lower impedance. Full article

This study explores the optimization of hydrometallurgical processes for recycling lithium-ion batteries (LIBs) containing a mixture of lithium iron phosphate (LFP) and nickel–manganese–cobalt (NMC) cathodes. Two approaches were investigated: acid-excess leaching and acid-deficient leaching with residue recirculation. A design of experiments (DoE) framework was applied to assess the impact of key parameters, including sulfuric acid and hydrogen peroxide concentrations, as well as solid-to-liquid (S/L) ratios, on the dissolution yields of target metals (Ni, Mn, Co, and Li). Acid-excess leaching achieved nearly complete dissolution of target metals but required additional purification steps to remove impurities. Acid-deficient leaching with a 60% recirculation of leaching residue improved dissolution yields by up to 12.5%, reduced reagent consumption, and minimized operational complexity. The study also evaluated separation strategies for manganese and cobalt through solvent extraction. Results indicate that while acid-excess leaching offers higher yields, acid-deficient leaching with residue recirculation is more cost-effective and environmentally friendly. These findings provide valuable insights for developing sustainable LIB recycling technologies. Full article

Batteries are widely used in energy storage systems (ESS), and thermal runaway in different types of batteries presents varying safety risks. Therefore, comparative research on the thermal runaway behaviors of various batteries is essential. This study investigates the thermal runaway characteristics of sodium-ion batteries (NIBs), lithium iron phosphate batteries (LFP), and lithium-ion batteries with NCM523 and NCM622 cathodes. The experiments were conducted in a nitrogen-filled constant-volume sealed chamber. The results show that the critical surface temperatures at the time of thermal runaway are as follows: LFP (346 °C) > NIBs (292 °C) > NCM523 (290 °C) > NCM622 (281 °C), with LFP batteries exhibiting the highest thermal runaway critical temperature. NIBs have the lowest thermal runaway triggering energy (158 kJ), while LFP has the highest (592.8 kJ). During the thermal runaway of all four battery types, the primary gases produced include carbon dioxide, hydrogen, carbon monoxide, methane, ethylene, propylene, and ethane. For NCM622 and NCM523, carbon monoxide is the dominant combustible gas, with volume fractions of 35% and 29%, respectively. In contrast, hydrogen is the main flammable gas for LFP and NIBs, with volume fractions of 44% and 30%, respectively. Among these, NIBs have the lowest lower flammability limit (LFL), indicating the highest explosion risk. The thermal runaway characteristics of 50 Ah batteries provide valuable insights for battery selection and design in energy storage applications. Full article

One-dimensional lithium-ion transport channels in lithium iron phosphate (LFP) used as a cathode in lithium-ion batteries (LIBs) result in low electrical conductivity and reduced electrochemical performance. To overcome this limitation, three-dimensional plasma-treated reduced graphene oxide (rGO) was synthesized in this study and used as an additive for LFP in LIB cathodes. Graphene oxide was synthesized using Hummers’ method, followed by mixing with LFP, lyophilization, and plasma treatment to obtain LFP@rGO. The plasma treatment achieved the highest degree of reduction and porosity in rGO, creating ion transfer channels. The structure of LFP@rGO was verified through scanning electron microscopy (SEM) analysis, which demonstrated that incorporating 10.0 wt% of rGO into LFP resulted in successful coverage by the rGO layer, forming LFP@rGO-10. In half-cell tests, LFP@rGO-10 exhibited a specific capacity of 142.7 mAh g⁻¹ at the 1.0 C-rate, which is higher than that of LFP. The full-cell exhibited 86.8% capacity retention after 200 cycles, demonstrating the effectiveness of rGO in enhancing the performance of LFP as an LIB cathode material. The outstanding efficiency and performance of the LFP@rGO-10//graphite cell highlight the promising potential of rGO-modified LFP as a cathode material for high-performance LIBs, providing both increased capacity and stability. Full article

Lithium iron phosphate (LiFePO₄ or LFP) is a promising cathode material for lithium-ion batteries (LIBs), but side reactions between the electrolyte and the LFP electrode can degrade battery performance. This study introduces an innovative coating strategy, using atomic layer deposition (ALD) to apply a thin (5 nm and 10 nm) Al₂O₃ layer onto high-mass loading LFP electrodes. Galvanostatic charge–discharge cycling and electrochemical impedance spectroscopy (EIS) were used to assess the electrochemical performance of coated and uncoated LFP electrodes. The results show that Al₂O₃ coatings enhance the cycling performance at room temperature (RT) and 40 °C by suppressing side reactions and stabilizing the cathode–electrolyte interface (CEI). The coated LFP retained 67% of its capacity after 100 cycles at 1C and RT, compared to 57% for the uncoated sample. Post-mortem analyses, including scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), were conducted to investigate the mechanisms behind the improved performance. These analyses reveal that Al₂O₃ coatings are highly effective in reducing LFP electrode degradation during cycling, demonstrating the potential of ALD Al₂O₃ coatings to enhance the durability and performance of LFP electrodes in LIBs. Full article

The rapid growth of electronic devices, electric vehicles, and mobile energy storage has produced large quantities of spent batteries, leading to significant environmental issues and a shortage of lithium resources. Recycling spent batteries has become urgent to protect the environment. The key to treating spent lithium-ion batteries is to implement green and efficient regeneration. This study proposes a recycling method for the direct regeneration of spent lithium iron phosphate (LFP) batteries using hydrothermal reduction. Ascorbic acid (AA) was used as a low-cost and environmentally friendly reductant to reduce Fe³⁺ in spent LiFePO₄. We also investigated the role of AA in the hydrothermal process and its effects on the electrochemical properties of the regenerated LiFePO₄ cathode material (AA-SR-LFP). The results showed that the hydrothermal reduction direct regeneration method successfully produced AA-SR-LFP with good crystallinity and electrochemical properties. AA-SR-LFP exhibited excellent electrochemical properties, with an initial discharge specific capacity of 144.4 mAh g⁻¹ at 1 C and a capacity retention rate of 98.6% after 100 cycles. In summary, the hydrothermal reduction direct regeneration method effectively repairs the defects in the chemical composition and crystal structure of spent LiFePO₄. It can be regarded as a green and effective regeneration approach for spent LiFePO₄ cathode materials. Full article

Commercialized lithium iron phosphate (LiFePO₄) batteries have become mainstream energy storage batteries due to their incomparable advantages in safety, stability, and low cost. However, LiFePO₄ (LFP) batteries still have the problems of capacity decline, poor low-temperature performance, etc. The problems are mainly caused by the following reasons: (1) the irreversible phase transition of LiFePO₄; (2) the formation of the cathode–electrolyte interface (CEI) layer; (3) the dissolution of the iron elements; (4) the oxidative decomposition of the electrolyte; (5) the repeated growth and thickening of the solid–electrolyte interface (SEI) film on the anode electrode; (6) the structural deterioration of graphite anodes; (7) the growth of lithium dendrites. In order to eliminate the problems, methods such as the modification, doping, and coating of cathode materials, electrolyte design, and anode coating have been studied to effectively improve the electrochemical performance of LFP batteries. This review briefly describes the working principle of the LFP battery, the crystal structure of the LFP cathode material, and its electrochemical performance as a cathode. The performance degradation mechanism of LFP batteries is summarized in three aspects—cathode material, anode material, and electrolyte—and the research status of LFP material modification and electrolyte design is emphatically discussed. Finally, the challenges and future development of LFP batteries are prospected. Full article

Recovering valuable metals from spent lithium-ion batteries (LIBs), a kind of solid waste with high pollution and high-value potential, is very important. In recent years, the extraction of valuable metals from the cathodes of spent LIBs and cathode regeneration technology are still rapidly developing (such as flash Joule heating technology to regenerate cathodes). This review summarized the studies published in the recent ten years to catch the rapid pace of development in this field. The development, structure, and working principle of LIBs were firstly introduced. Subsequently, the recent developments in mechanisms and processes of pyrometallurgy and hydrometallurgy for extracting valuable metals and cathode regeneration were summarized. The commonly used processes, products, and efficiencies for the recycling of nickel–cobalt–manganese cathodes (NCM/LCO/LMO/NCA) and lithium iron phosphate (LFP) cathodes were analyzed and compared. Compared with pyrometallurgy and hydrometallurgy, the regeneration method was a method with a higher resource utilization rate, which has more industrial application prospects. Finally, this paper pointed out the shortcomings of the current research and put forward some suggestions for the recovery and reuse of spent lithium-ion battery cathodes in the future. Full article

This paper presents an experimental comparison of two types of Li-ion battery stacks for low-voltage energy storage in small urban Electric or Hybrid Electric Vehicles (EVs/HEVs). These systems are a combination of lithium battery cells, a battery management system (BMS), and a central control circuit—a lithium energy storage and management system (LESMS). Li-Ion cells are assembled with two different active cathode materials, nickel–cobalt–aluminum (NCA) and lithium iron phosphate (LFP), both with an integrated decentralized BMS. Based on experiments conducted on the two assembled LESMSs, this paper suggests that although LFP batteries have inferior characteristics in terms of energy and power density, they have great capacity for improvement. Full article