A review on the recycling of spent lithium iron phosphate batteries

Efficient non-destructive recovery of LiFePO4 from spent lithium-Ion batteries for high-purity regeneration

Following mechanical shredding of spent lithium-ion batteries (LIBs), the complex composition of electrode materials hinders subsequent recycling. Thus, the separation of cathode and anode materials is a crucial step in the recycling process. The separation efficiency of cathode and anode materials under the two pretreatment methods of oxygen-free roasting and water soaking was analyzed by testing and calculation. Based on the different pyrolysis characteristics, the pretreatment process through oxygen-free roasting achieved high-purity separation, yielding anode and cathode materials with purities of 98.5 % and 93.3 %, respectively. By exploiting the water solubility differences of the binders, soaking the electrode sheets in water for 75 min followed by 40 KHz frequency ultrasonication for 1 min before sieving results in a purity of up to 98.7 % for the anode material and 98.1 % for the cathode material. Additionally, the anode material's lithium leaching rate during water soaking separation is 82.9 %, supplying raw material for cathode repair and regeneration. Furthermore, the initial charge-discharge specific capacity of cathode material separated by water soaking is around 150 mAh/g after lithium replenishment, which is significantly higher than that of cathode material separated by oxygen-free calcination. A novel process for separating cathode and anode materials through water soaking and ultrasonic vibration was ultimately developed. This process not only enables the efficient separation of LiFePO4 cathode materials but also facilitates their high-value regeneration. This method offers a scalable and environmentally sustainable approach to LIB recycling, with potential applications in industrial-scale battery material recovery.

A review on the insights into redox-based regeneration strategies for LiFePO4 batteries

In recent years, the market share of lithium iron phosphate (LiFePO4: LFP) batteries within the power battery sector has witnessed substantial growth. In light of low-carbon initiatives and environmental sustainability, the recycling of spent LiFePO4 (SLFP) batteries, especially their regeneration, is of paramount importance for environmental protection, resource conservation, and enhancement of economic efficiency. Current literature reviews predominantly concentrate on synthesizing existing research from the perspective of regeneration methodologies. However, they insufficiently address the chemical reactions that are integral to the regeneration process, which are essential for optimizing the recycling of SLFP batteries. To address this gap in the literature, this review, for the first time, systematically compiles studies from the innovative perspective of redox reactions occurring during the regeneration of SLFP batteries. This review commences with an analysis of the economic benefits and failure mechanisms linked to the regeneration of SLFP batteries, thereby elucidating the rationale and necessity for this process. Subsequently, it delves into indirect regeneration methods based on oxidation reactions and direct regeneration technologies based on reduction reactions. Furthermore, the review underscores research dedicated to the enhancement and repurposing of SLFP battery cathodes, offering a prospective outlook on the novel trends in the recycling of SLFP battery materials. This review aspires to promote further scholarly inquiry into the regeneration of SLFP batteries.

A novel method for selective lithium recovery from end-of-life LiFePO4 automotive batteries via thermal treatment combined with a leaching process

As the demand for electric vehicles increases, effective solutions for recycling end-of-life lithium-ion batteries become crucial. Since lithium iron phosphate (LFP) batteries represent a significant portion of the automotive battery market, this research introduces an innovative method to produce concentrated lithium solutions by combining a calcination process with a microwave-assisted hydrometallurgical process. The initial steps involve safe collection and disassembly of discarded batteries to preserve components and minimize contamination. The cathode coils are separated and ground to a particle size smaller than 0.25 mm, concentrating 96% of the lithium compounds. Afterward, the cathode material undergoes calcination for 1 h at temperatures ranging from 300 to 900 °C in air and N₂ atmospheres. For samples treated in an oxidative atmosphere, the complete phase conversion of LiFePO₄ to Li₂Fe₃(PO₄)₃ occurs at 500 °C, whereas in an inert atmosphere, this phase change fully manifests at 700 °C. Different sulfuric acid concentrations (0.5, 1.0, and 1.5 mol/L) are subsequently used in the microwave-assisted leaching process for all the calcined and non-calcined cathodic powders. Using leaching with aqua regia as a reference for the complete leaching of metals, the best results in terms of lithium selectivity are achieved with samples calcined at 500 °C and leached with 0.5 mol/L sulfuric acid. Under these conditions, 75% of all the lithium and only 2.5% of all the iron are extracted in solution. This result demonstrates that calcination in an air atmosphere prior to a hydrometallurgical process plays a fundamental role in achieving high lithium selectivity without the need for any other additives.

Sustainable Hydrometallurgical LFP Battery Recycling: Electrochemical Approaches

Lithium-ion batteries (LIBs) are crucial for the energy transition, particularly with the rising demand for electric vehicles. Among different battery technologies, lithium iron phosphate (LFP) batteries have been attracting considerable attention in recent years due to their safe chemistry and relatively cheaper and abundant material composition. As LFP manufacturing is set to increase significantly, a proper end-of-life treatment of these batteries becomes essential to achieve circularity and minimize environmental impacts. However, recycling of LFP batteries is economically challenging because they do not contain many valuable transition metals. This Concept article focuses on recycling of LFP batteries, and explores whether economically viable LFP recycling can be made possible via improvement of recycling processes. Currently, hydrometallurgical recycling processes with inexpensive oxidants for leaching valuable lithium show potential, compared to pyrometallurgical processes. However, these processes still consume large amounts of chemicals. Electrochemical recycling methods that do not require continuous addition of external reagents, or minimize waste production, could lead to more sustainable and economically viable solutions for LFP battery recycling. In addition, combining these processes with other sustainable electrochemical technologies such as green hydrogen production, brine desalination and chemical production is a promising strategy to increase overall energy and product efficiency.

Research on accelerating the recycling efficiency of waste batteries for new energy vehicles based on a stochastic evolutionary game model

Although the rapid development of new energy vehicles (NEV) has contributed greatly to China's carbon emission reduction, it has also brought about a problem that needs to be solved, namely the effective recycling of waste batteries. Existing recycling of waste batteries is plagued by a series of problems such as a single recycling channel, inconsistent recycling standards, lack of recycling technology, rampant irregular recycling enterprises, and low consumer participation. Meanwhile, due to the immaturity of the recycling market, the lack of clarity of existing regulations, and the lack of supervision and management, the above problems are becoming more and more serious. Therefore, to solve these problems, this paper constructs a four-party stochastic evolutionary game model including government regulators, NEV enterprises, third-party recycling enterprises, and consumers. Focus on analyzing the impact of relevant parameters on the choice of strategies by participants, and put forward proposed countermeasures to promote the effective recycling of waste batteries based on the conclusions.

A review on direct regeneration of spent lithium iron phosphate: From waste to wealth

Lithium iron phosphate (LFP) batteries are widely used due to their affordability, minimal environmental impact, structural stability, and exceptional safety features. However, as these batteries reach the end of their lifespan, the accumulation of waste LFP batteries poses environmental hazards. Recycling these batteries is crucial for mitigating pollution risks and enabling secondary resource utilization. Traditional metallurgical recycling methods offer limited economic returns for waste LFP batteries due to their relatively low value compared to other types of cathode materials. Therefore, direct regeneration has emerged as a simpler, more cost-effective, and promising alternative. Given the stable crystal structure of LFP after decommissioning, direct regeneration by repairing lithium vacancy defects presents significant potential. This paper critically reviews the research progress on LFP regeneration, particularly focusing on developments over the past five years, and evaluates the industrial feasibility and pros and cons of these methods. Grounded in the concepts of wealth and waste, this paper adopts a novel perspective to discuss the processes of LFP degeneration and regeneration. It examines the dual attributes of waste and wealth in waste LFP batteries, elucidating the relationship and transformation between these two aspects. In particular, the paper discusses the value of LFP in its three forms-new, second-life, and waste-and the environmental and safety impacts of waste LFP batteries. It emphasizes the importance of converting waste into wealth and the role of regeneration as a potential means in the LFP recycling process. The paper objectively assesses the current challenges and opportunities, aiming to provide insights into the importance of LFP battery recycling and to explore potential avenues for advancing regeneration technologies through this comprehensive review.

Optimization of resource recovery technologies in the disassembly of waste lithium batteries: A study on selective lithium extraction

This study focuses on optimizing resource recovery technology in the dismantling process of retired lithium batteries to mitigate environmental pollution. Addressing the challenge of significant precious metal losses in traditional hydrometallurgical recycling methods, this study employs a reductive roasting-carbonation leaching process to selectively extract lithium from cathode materials using a reducing agent. The study examines the effects of parameters such as roasting temperature, time, and reducing agent dosage on lithium leaching efficiency, and explores additional factors including carbonation leaching time, carbon dioxide flow rate, liquid-to-solid ratio, and leaching temperature in conjunction with multi-stage countercurrent leaching technology. Characterization of the roasting products and leaching process is performed using X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The results demonstrate that, under conditions of a 700 °C roasting temperature, a 3-h roasting time, and a 15 % reducing agent dosage, the lithium leaching rate can achieve approximately 90 %. Following multi-stage countercurrent leaching, the lithium leaching rate exceeds 97 %, satisfying the purity requirements for battery-grade lithium carbonate. The innovation of this study is evident in its optimization of the recycling process, effectively separating and recovering cathode materials while reducing environmental pollution. This approach supports environmentally friendly waste treatment and contributes to the sustainable development of the battery industry.

High-efficiency leaching process for selective leaching of lithium from spent lithium iron phosphate

With the arrival of the scrapping wave of lithium iron phosphate (LiFePO4) batteries, a green and effective solution for recycling these waste batteries is urgently required. Reasonable recycling of spent LiFePO4 (SLFP) batteries is critical for resource recovery and environmental preservation. In this study, mild and efficient, highly selective leaching of lithium from spent lithium iron phosphate was achieved using potassium pyrosulfate (K2S2O7) and hydrogen peroxide (H2O2) as leaching agents. The leaching rates of lithium and iron were 99.83 % and 0.34 %, respectively, at the optimal leaching conditions of 4 vol% 30 wt% H2O2, 0.08 mol/L K2S2O7, 25℃, 5 min, and a solid-liquid ratio of 20 g/L. Meanwhile, the mechanism of the leaching process was explored by thermodynamic, XRD, XPS, FTIR, and SEM analyses. The leaching solution was concentrated and purified, with the addition of potassium carbonate (K2CO3) to convert lithium into lithium carbonate (Li2CO3). A small amount of sulfuric acid (H2SO4) is added to the saline wastewater after precipitation, which can be converted into a leaching agent for recycling after heat treatment. This study provides a sustainable green process for the recovery of lithium iron phosphate and a new idea for resource recovery.

Recycling of Spent Lithium Iron Phosphate Cathodes: Challenges and Progress

The number of spent lithium iron phosphate (LiFePO4, LFP) batteries will increase sharply in the next few years, owing to their large market share and development potential. Therefore, recycling of spent LFP batteries is necessary and urgent from both resource utilization and environmental protection standpoints. In this review, the significance of pretreatment for LFP recycling is first underscored, and its technical challenges and recent advancements are presented. Following that, the current recycling methods for spent LFP cathodes are outlined in terms of the respective treating processes, advantages, and disadvantages. Additionally, the preparation methods of LFP cathode material are reviewed to guide the resynthesis of LFP that uses salts obtained from spent LFP, which are beneficial for closed-loop recycling of LFP batteries. Lastly, we explore the future development direction of spent LFP battery recycling, highlighting the importance of technological innovation to advance the sustainable growth of the LFP battery industry.

A Method of Efficiently Regenerating Waste LiFePO4 Cathode Material after Air Firing Treatment

Waste LiFePO4 (LFP) batteries can be harmful to the environment and lead to waste of resources if not properly disposed of. In this study, an efficient and environmentally friendly method for solid-phase recycling waste LFP cathode material (W-LFP) is proposed. Most of the impurities in the W-LFP are removed by air firing. The regenerated LFP is then obtained by adding lithium carbonate and triethanolamine for repair during heat treatment. The addition of triethanolamine converts Fe3+ to Fe2+ and also allows the formation of an N-doped modified carbon layer on the surface of the LFP particles, which improves the electrochemical properties of the regenerated material. Physical characterization and electrochemical tests are used to investigate the attenuation and regeneration mechanism of LFP. The regenerated LFP possesses a high specific discharge capacity (152.87 mAh g-1 at 0.2 C), which is about 95.32% of the commercial LFP, and the capacity retention rate is 88.52% after 600 cycles at 1 C. It is worth noting that we do not use solvents such as acids and alkalis in the regeneration process, thus avoiding the generation of large quantities of acid and alkaline waste liquids, which is friendly to the environment. This solid-phase regeneration process offers a promising method for the future recycling of used LFP batteries because of its simplicity, environmental friendliness, and high efficiency.

Crystal phase and nanoscale size regulation utilizing the in-situ catalytic pyrolysis of bamboo sawdust in the recycling of spent lithium batteries

Current Li-ion battery (LIB) recycling methods exhibit the disadvantages of low metal recovery efficiencies and high levels of pollution and energy consumption. Here, products generated via the in-situ catalytic pyrolysis of bamboo sawdust (BS) were utilized to regulate the crystal phase and nanoscale size of the NCM cathode to enhance the selective Li extraction and leaching efficiencies of other valuable metals from spent LIBs. The catalytic effect of the NCM cathode significantly promoted the release of gases from BS pyrolysis. These gases (H2, CO, and CH4) finally transformed the crystal phase of the NCM cathode from LiNixCoyMnzO2 into (Ni-Co/MnO/Li2CO3)/C. The size of the spent NCM cathode material was reduced approximately 31.7-fold (from 4.1 μm to 129.2 nm) after roasting. This could be ascribed to the in-situ catalytic decomposition of aromatic compounds generated via the primary pyrolysis of BS into C and H2 on the surface of the cathode material, resulting in the formation of the nanoscale composite (Ni-Co/MnO/Li2CO3)/C. This process enabled the targeted control of the crystal phase and nanoscale size of the material. Water leaching studies revealed a remarkable selective Li extraction efficiency of 99.27 %, and sulfuric acid leaching experiments with a concentration of 2 M revealed high extraction efficiencies of 99.15 % (Ni), 93.87 % (Co), and 99.46 % (Mn). Finally, a novel mechanism involving synergistic thermo-reduction and carbon modification for crystal phase regulation and nanoscale control was proposed. This study provides a novel concept for use in enhancing the recycling of valuable metals from spent LIBs utilizing biomass waste and practices the concept of "treating waste with waste".

A clean and sustainable method for recycling of lithium from spent lithium iron phosphate battery powder by using formic acid and oxygen

With the widespread adoption of lithium iron phosphate (LiFePO4) batteries, the imperative recycling of LiFePO4 batteries waste presents formidable challenges in resource recovery, environmental preservation, and socio-economic advancement. Given the current overall lithium recovery rate in LiFePO4 batteries is below 1 %, there is a compelling demand for an eco-friendly, cost-efficient, and sustainable solution. This study introduces a green and sustainable recycling method that employs environmentally benign formic acid and readily available oxygen as reaction agents for selectively leaching lithium from discarded lithium iron phosphate powder. Formic acid was employed as the leaching agent, and oxygen served as the oxidizing agent. Utilizing a single-factor variable approach, various factors including formic acid concentration, oxygen flow rate, leaching time, liquid-to-solid ratio, and reaction temperature were individually investigated. Moreover, the feasibility of this method was explored mechanistically by analyzing E-pH diagrams of the Li-Fe-P-H2O system. Results demonstrate that under conditions of 2.5 mol/L formic acid concentration, 0.12 L/min oxygen flow rate, 25 mL/g liquid-to-solid ratio, 70 °C reaction temperature, and 3 h reaction time, lithium leaching efficiency exceeds 99.9 %, with iron leaching efficiency only at 1.7 %. Moreover, we also explored using air instead of oxygen as the oxidant and get the excellent lithium leaching rate (97.81 %) and low iron leaching rate (4.81 %), which shows the outstanding selectivity. Furthermore, the environmentally benign composition of the chemical reagents, comprising only C, H, and O elements, establishes it as a genuinely green and sustainable technology for secondary resource recovery. It can be considered as a highly environmentally friendly, cost-effective, and efficient approach. Nevertheless, in the current context of carbon neutrality and sustainable development, this method undoubtedly holds excellent prospects for industrialization.