Search Results (1,124)

Gel polymer electrolytes (GPEs) have emerged as promising electrolytes for lithium metal batteries owing to their high ionic conductivity, mechanical flexibility, and reduced risk of electrolyte leakage. However, PAN-based GPEs still suffer from limited ion transport caused by the semi-crystalline structure of PAN chains. In this work, polyacrylonitrile (PAN)/poly(methyl methacrylate) (PMMA)/lithium aluminum titanium phosphate (LATP)/lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) gel polymer electrolytes were fabricated via direct ink writing (DIW) 3D printing, where PMMA was introduced to regulate the PAN matrix and enhance Li⁺ transport. The results reveal that PMMA incorporation effectively reduces PAN crystallinity, increases the amorphous fraction, and modifies the local functional-group environment of the polymer matrix, while LATP fillers further improve ionic transport and mechanical stability. The optimized PPM8:2 gel polymer electrolyte delivers a room-temperature ionic conductivity of 4.22 × 10⁻⁴ S cm⁻¹, a Li⁺ transference number of 0.624, and an electrochemical stability window of 4.75 V. When applied in LiFePO₄|Li batteries, it maintains a discharge capacity of approximately 150 mAh g⁻¹ after 100 cycles at 0.1 C with excellent rate capability and cycling stability. This work provides an effective approach to developing PAN-based gel polymer electrolytes for high-performance lithium metal batteries. Full article

Lithium-ion batteries (LIBs) with high energy density and long cycle life are extensively used in electric vehicles, energy storage systems, and other applications, which simultaneously leads to a large number of spent LIBs. Although a large number of spent LIBs pose a serious threat to the environment and human health, timely recovery and disposal of valuable metals in LIBs are crucial for mitigating the scarcity of Li, Ni, and Co resources and reducing environmental hazards in China. This study first disassembled the positive electrode materials of used lithium-ion batteries to obtain ternary powders; then, calcination was carried out under a CO₂ atmosphere, and finally lithium was efficiently extracted via hot water leaching. Subsequently, the insoluble residue was leached with nitric acid, and NaOH was added to the resulting mixed metal ion solution to adjust the pH, yielding a Ni-Co-Mn precursor. Finally, a series of NCM/TiO₂ catalysts using TiO₂ as a support are synthesized via an impregnation method for low-temperature NH₃-SCR reactions. The results indicate that the NCM/TiO₂ catalysts exhibit optimal catalytic activity over the temperature range of 220–300 °C. Notably, the catalyst with 14 wt% Mn achieves over 85% NO conversion at 220 °C. On the whole, the NCM/TiO₂ catalysts can effectively promote the adsorption and activation of NH₃ and NO through rich oxygen vacancies and a high density of surface acid sites. This work provides a novel technical pathway and a theoretical foundation for the value-added utilization of spent LIBs. Full article

Lithium-oxygen (Li-O₂) batteries are a compelling next-generation energy storage candidate owing to their ultrahigh theoretical specific energy, but their practical deployment is critically limited by sluggish cathodic oxygen reduction/evolution kinetics, severe polarization, and poor cyclability. Here, we design a composite catalyst consisting of ultrasmall iron clusters uniformly anchored on a three-dimensional nitrogen-doped carbon aerogel (Fe@NC). The material is synthesized via bidirectional freeze-drying followed by high-temperature reduction carbonization using chitosan, cellulose nanocrystals, and zinc acetate; sublimation of zinc during pyrolysis effectively suppresses iron aggregation, yielding highly dispersed Fe0 clusters of ~10 nm while preserving the aerogel’s hierarchical porous architecture rich in pyridinic and pyrrolic N species. Electrochemical tests show that Fe@NC delivers a deep-discharge specific capacity of 18,000 mAh/g, substantially outperforming pristine carbon aerogel and commercial Ketjen black, and maintains stable cycling over 280 cycles at 500 mAh/g. Microscopic and spectroscopic analyses confirm that Fe@NC promotes uniform, fine-particle Li₂O₂ deposition without pore blockage and enables its complete reversible decomposition upon charging, effectively mitigating electrode passivation. This work demonstrates that the synergistic combination of carbon aerogel mass-transport benefits and iron cluster catalytic activity provides a viable, scalable route to high-performance Li-O₂ battery cathodes. Full article

Lithium–sulfur (Li-S) batteries are widely regarded as one of the most promising candidates for next-generation electrochemical energy storage, owing to their very high theoretical energy density and reliance on abundant, low-cost elements. However, the practical deployment of Li-S technology remains severely constrained by the polysulfide shuttle effect, originating from the dissolution, migration and parasitic redox cycling of lithium polysulfide intermediates, which leads to rapid capacity fading, low coulombic efficiency and incompatibility with industrial carbonate-based electrolytes. Recent reports on the formation and stabilization of γ-sulfur, a rare monoclinic allotrope, within porous carbon matrices have identified a prospective direction in sulfur electrochemistry, theoretically enabling polysulfide-free cycling and improved stability, also in conventional carbonate electrolytes. These findings challenge the long-held assumption that polysulfide formation is unavoidable in sulfur cathodes and suggest that control over sulfur allotropy and nanoconfinement, as well as carbon–sulfur chemistry, may unlock previously inaccessible performance and integration windows for metal–sulfur batteries, including most technologically advanced Li-S batteries. Based on recent studies, this Perspective article critically evaluates the evidence for γ-sulfur stabilization in carbon hosts, discusses the interplay between pore geometry, carbon surface chemistry and sulfur speciation, and finally identifies key knowledge gaps. Full article

The limitations of conventional inorganic electrodes call for organic alternatives for advanced energy storage. Metal–covalent organic frameworks (MCOFs) integrate the metal active sites of metal–organic frameworks (MOFs) with the high chemical stability imparted by strong covalent bonds in covalent organic frameworks (COFs) while retaining the high specific surface area and tunable porosity of both material classes. Among these, MCOFs constructed from porphyrin and phthalocyanine building units have emerged as a research hotspot in electrochemical energy storage owing to their inherent 18π-conjugated macrocyclic electronic systems, well-defined M–N₄ coordination sites, and potential bipolar charge storage characteristics. This review systematically summarizes recent advances in this class of materials. First, from the perspective of metal center introduction timing, three core synthetic strategies—pre-metallation, simultaneous metallation, and post-metallation—are categorized and evaluated in terms of coordination precision, synthetic efficiency, and scalability potential. Second, the regulatory effects of two-dimensional layered and three-dimensional interpenetrated structures on charge transport pathways and structural stability are elucidated. Subsequently, the applications of porphyrin/phthalocyanine-based MCOFs in lithium-based batteries, zinc-based batteries, sodium/potassium-ion batteries, and supercapacitors are reviewed in detail, with emphasis on the key roles of metal active sites in catalytic conversion, chemical anchoring/confinement, interface stabilization, and pseudocapacitive contribution. Finally, future directions to address key performance and mechanistic bottlenecks are discussed. This review aims to provide a systematic reference for the rational design and energy storage applications of high-performance porphyrin/phthalocyanine-based MCOFs. Full article

Effective thermal management is a cornerstone of safe, long-life lithium-ion battery operation, especially under high-rate charge–discharge and dynamic driving conditions. Conventional active cooling technologies face inherent trade-offs between heat dissipation efficiency, system complexity, and temperature uniformity, while phase change materials (PCMs) provide a promising passive alternative by absorbing latent heat during phase transition to buffer temperature spikes, improve temperature uniformity, and delay thermal runaway propagation. This paper presents a comprehensive review of recent advances in PCM-based lithium-ion battery thermal management, systematically covering the full scope from fundamental battery heat generation mechanisms to material synthesis optimization and hybrid system integration. At the material level, we analyze state-of-the-art strategies to address the intrinsic drawbacks of organic PCMs—low thermal conductivity, mismatched phase transition temperatures, and high flammability—including the construction of carbon/metal conductive skeletons, compositional tuning of phase change behavior, and flame-retardant modifications. These approaches have yielded composite PCMs with significantly improved heat transport capability and fire safety, while preserving high latent heat storage capacity. At the system level, we evaluate the thermal performance of pure passive PCM configurations, which excel at peak temperature suppression and inter-cell temperature uniformity, as well as hybrid designs that combine PCMs with air or liquid cooling to resolve heat accumulation issues and maintain stable performance under prolonged, demanding operating cycles. Despite these advances, key challenges remain: balancing high thermal conductivity with high latent heat capacity, developing climate-adaptable phase transition temperatures, and integrating multiple functionalities without compromising core thermal storage properties. Looking forward, future research directions include multifunctional integrated composites, smart adaptive PCMs, cost-effective scalable manufacturing, and precision structural engineering. This review also summarizes quantified performance trade-offs and provides actionable design guidelines for both material development and system-level integration. Full article

Lithium–sulfur batteries have become one of the research focuses of scientists over the past decade due to their high theoretical specific capacity (approximately 1670 mAh/g), low cost, and environmental friendliness, and the abundant reserves of their raw materials. Nevertheless, they still suffer from inherent drawbacks including poor electrical conductivity of elemental sulfur, electrode volume expansion during charge–discharge cycles, the shuttle effect and lithium dendrite growth, which severely restrict their practical application and industrialization. To address the above issues, extensive research has been carried out to optimize cathode materials, separators and electrolytes. In particular, the shuttle effect occurring during cycling can be effectively mitigated via separator modification. This paper briefly introduces the design strategies for separators for lithium–sulfur batteries, and mainly summarizes separator-modification methods using carbon materials, graphene, carbon nanotubes, heteroatoms, polymers, metal–organic frameworks (MOFs) and covalent organic frameworks (COFs). Finally, the future development trends of lithium–sulfur batteries are prospected. Full article

The rapid growth of tennis participation and the widespread use of lithium-ion batteries have led to increasing volumes of rubber waste and spent battery materials, underscoring the need for integrated recycling strategies. In this work, a thermochemical co-pyrolysis process is developed to convert waste tennis ball rubber particles (TBRPs) and spent lithium-ion battery (LIB) cathodes into valuable products. The decomposition of TBRPs generates reactive gaseous and liquid hydrocarbons that function as in situ reductants, enabling the breakdown of high-valence transition metal oxides in the cathode material. Subsequent magnetic separation and mild acid-washing yield nonmagnetic solids enriched in lithium compounds and carbonaceous residues. Structural and chemical analyses (SEM, XRD, TEM, EDS, and XPS) confirm extensive cathode reduction and the formation of Li₂CO₃ at optimized conditions (650 °C, 1 h, cathode-to-TBRPs mass ratio 1:0.65). The carbonized rubber evolves into a highly porous carbon material with a carbon purity of approximately 95.37 At%. This study demonstrates a low-energy, environmentally friendly pathway for the co-valorization of two challenging waste streams while simultaneously recovering lithium salts, reduced metal oxides, and functional porous carbon. Full article

Lithium metal batteries are widely regarded as one of the most promising candidates for achieving energy densities beyond 500 Wh kg⁻¹. However, their practical commercialization is severely hindered by the high reactivity of lithium metal, which leads to pronounced interfacial instability. Constructing an artificial solid electrolyte interphase (SEI) via surface pretreatment has been demonstrated to be an effective strategy for suppressing dendrite growth and mitigating parasitic side reactions. Herein, we take advantage of the rapid reaction between lipoic acid (LA) and lithium metal to pre-form a uniform artificial SEI on the anode surface. This interphase is composed of organic COO-Li species and sulfur-containing compounds. Electrochemically, the LA-modified lithium anode exhibits remarkable stability, sustaining more than 1500 h of cycling in symmetric cells at 5 mA cm⁻² and 5 mAh cm⁻². Furthermore, full-cell configurations, including lithium-sulfur and lithium-LiFePO₄ pouch cells, deliver significantly improved cycling performance compared with those employing bare lithium anodes. These results establish a practical and scalable route for fabricating stable artificial SEI layers on lithium metal, thereby providing a feasible pathway toward the realization of high-energy-density lithium metal batteries. Full article

Buried interfaces and interphases often govern performance loss in rechargeable batteries, although their functions are frequently inferred from spatially averaged composition, surface-sensitive measurements, or cell-level electrochemical response. In this Perspective, an interface denotes the geometrical boundary between adjacent phases, whereas an interphase denotes a finite-thickness region whose composition or structure differs from those of the adjoining bulk phases. Rather than organizing the discussion by focused ion beam (FIB) modality or battery chemistry alone, we adopt an architecture-first, evidence-bounded framework and compare three classes of buried-interface architecture: engineered particle coatings; electrochemically generated solid electrolyte interphase (SEI) and cathode–electrolyte interphase (CEI) regions together with lithium-metal deposits; and solid–solid contacts in all-solid-state batteries. For each class, the formation route and required function are related to spatial descriptors, including thickness distribution, lateral continuity, pore or gap topology, chemical gradients, contact area, and contact retention. FIB-enabled cross-sectioning, tomography, and correlative spectroscopy can register morphology, chemistry, and contact geometry within a common spatial frame, but they do not directly measure ionic conductivity, electronic leakage, adhesion energy, or local reaction rate. Such functional attribution therefore requires complementary electrochemistry, spectroscopy, modeling, temporal observation, and representative sampling. Across the three classes, durable interfacial function depends on chemically selective transport pathways that remain spatially continuous and mechanically viable during processing, cycling, and storage. Full article

Battery thermal management systems (BTMSs) are essential for maintaining the performance, efficiency, durability, and safety of electric-vehicle battery packs. Although fin-enhanced air-cooled BTMSs offer a simple and leakage-free cooling solution, their practical implementation is often limited by increased weight, insufficient temperature uniformity, and restricted heat-dissipation capability under high thermal loads. This study numerically investigates a compact air-cooled BTMS for two types of cylindrical lithium-ion batteries using aluminum and polypropylene (PP-$\beta$) circumferential fins in inline and staggered cell arrangements. Unlike previous fin-based air-cooling investigations, the present study combines a compact 2 × 4 battery pack with transverse and longitudinal center-to-center cell pitches of 1.2D, a direct comparison between metallic and lightweight polymer fins, and an assessment of two 18650 battery types with different capacities, thermophysical properties, and heat-generation characteristics. A three-dimensional steady-state conjugate heat-transfer model was developed in ANSYS Fluent to evaluate the effects of fin number, fin material, cell arrangement, ambient temperature, and inlet airflow velocity under discharge rates ranging from 1 C to 4 C. The results reveal that increasing the number of fins consistently reduced the maximum cell temperature but increased the pressure drop. The inline configuration generally achieved a lower maximum temperature and higher Nusselt number (Nu), whereas the staggered arrangement maintained a substantially lower pressure drop. Relative to the corresponding finless configurations, the Nu increased by 64.4–71.2% for the inline arrangement and 86.4–98.1% for the staggered arrangement. Polypropylene fins provided thermal performance close to that of aluminum fins in terms of maximum temperature while reducing the total fin mass by approximately 44.8%; however, aluminum fins maintained better temperature uniformity. These findings quantify the trade-offs among thermal performance, pressure drop, compact cell spacing, and system weight, providing design guidance for compact fin-enhanced air-cooled BTMSs. Full article

This study investigated how acid concentration affects leaching from pyrolyzed LIBs’ (lithium-ion batteries’) black mass (BM) by stepwise acidification with eight acids at 70 °C under identical starting conditions. A citric-acid control without BM matched the calculated pH, whereas BM buffered solutions to ∼pH 9.5 and increased the measured pH. Stabilized pH provided a consistent reference within each experiment, but similar pH values across acids produced very different leaching efficiencies. At pH ≈ 3, lithium leaching was ∼pH 85% for formic acid and ∼pH 60% for citric acid. The maximum lithium leaching ranged from 49% (ascorbic acid) to 92% (sulfuric acid), while organic acids often showed limited cobalt and nickel dissolution. For formic acid, speciation and metal-formate solubility calculations showed that higher acid concentration does not necessarily increase transition-metal leaching and may suppress cobalt and nickel. Thus, pH is stable within each acid system but not transferable across acids, and high solid loading (250 g L⁻¹) further requires acid-specific evaluation. The results indicate that acid-dependent speciation and complexation, rather than proton concentration alone, control extraction and can decouple acid dosage from leaching performance. Full article

Recycling of lithium-ion batteries (LIBs) remains challenging due to high energy requirements, losses of key elements like lithium, and the heterogeneity of waste streams arising from different cathode chemistries. This study evaluates multiple recycling methods for LIBs black mass (BM), to recover critical raw materials and other valuable components. Three types of BM including nickel–manganese–cobalt (NMC), lithium iron phosphate (LFP) and a heterogeneous mixture of cell phones and laptops (HL; German: Handy/Laptops), were treated using froth flotation, pyrometallurgy, and biohydrometallurgy and their respective recovery efficiencies were assessed. The flotation results revealed that the HL sample had the lowest mis-recovery of non-ferrous metals into the froth product (around 10%), leading to further flotation only for HL. During screening, 94–99% of iron, phosphorus, and carbon in LFP-type BM were recovered in the fine fraction (<45 µm), while 92–99% of lithium, cobalt, manganese, nickel, and carbon in NMC-type BM were recovered in the same fraction. During precipitation, 99% of iron and 100% of phosphorus were recovered from LFP bioleachates at pH 3, while ~97–100% of dissolved cobalt, manganese, and nickel were recovered from NMC bioleachates. These findings confirm that no single recycling method is optimal for all battery chemistries. Full article

Reaching the end of their lifecycle, lithium-ion batteries contain significant amounts of lithium residues as well as valuable metals such as Co, Ni, and Mn, presenting both environmental risks and opportunities for resource recovery. Recent advances in hydrometallurgical, pyrometallurgical, and biotechnological methods enable the recovery of high-purity lithium compounds while also increasing their economic viability. This study analyzes the contribution of lithium recovery methods to sustainability criteria, their annual averages, and total data between 2008 and 2026, considering the number of academic references in the literature. The analysis compares the contributions of recycling methods to lithium and other metal recovery efficiency, process efficiency, energy consumption, environmental impact, economic impact, adaptation to technological developments, and integrated applications. LIB recycling methods showed higher overall and annual average sustainability contributions to the recovery efficiency of other metals and lithium compared to other criteria. Their contributions to process efficiency and the environment were also relatively high. However, their contributions to the economy, adaptation to technological developments, and integration of methods remain low. Furthermore, since the contribution to energy consumption is negative overall, further academic studies are needed to improve contributions, particularly in energy consumption and the other three criteria mentioned above. Full article

The rapid increase in electric vehicles has increased the generation of spent lithium-ion batteries (LIBs) and the need for efficient lithium recovery technologies. This study compared two distinct sulfation roasting routes, using sodium sulfate (Na₂SO₄) at 750 °C and sulfuric acid (H₂SO₄) at 550 °C, applied to black mass derived from lithium iron phosphate (LFP) and lithium nickel manganese cobalt oxide (NCM) batteries. Metal extraction efficiencies were determined by inductively coupled plasma optical emission spectrometry, while reaction products were identified by X-ray diffraction analysis. Sulfation roasting using Na₂SO₄ resulted in low lithium recovery for both materials, with maximum extractions of 5.7% for LFP and 24.5% for NCM. In contrast, H₂SO₄-assisted roasting achieved high lithium recovery from NCM black mass, reaching 90.8%, 91.5%, and 88.5% at 45, 90, and 180 min at 550 °C, respectively, with lithium predominantly converted into water-soluble lithium sulfate. Lithium extraction from LFP black mass remained below 13% under all conditions. Statistical analysis confirmed that lithium recovery at 45 min was equivalent to longer residence times, while prolonged roasting increased manganese coextraction and altered cobalt and nickel behavior. Overall, sulfuric acid-assisted sulfation roasting is an efficient and energy-favorable route for lithium recovery from NCM black mass, whereas sulfation roasting is unsuitable for LFP materials, under the tested conditions. The results highlight the importance of cathode chemistry segregation and demonstrate the feasibility of reducing processing time without compromising lithium recovery. Full article