Advanced strategies for enhancing performance and sustainability in lithium iron phosphate batteries

Selective bioleaching of lithium from waste lithium iron phosphate batteries using spent medium produced by Acidithiobacillus thiooxidans

The rapid increase in spent lithium iron phosphate (LFP) batteries from electric and hybrid vehicles highlights the urgent need for sustainable and economically viable recycling methods. This study presents an innovative recycling process that efficiently recovers lithium and iron from spent LFP batteries using citric-acid leaching combined with Fenton oxidation (Fe2+/H2O2 system) to generate hydroxyl radicals for enhanced LiFePO4 dissolution. The process includes four steps: citric-acid leaching to release lithium and iron, removal of excess citric acid using lead sulfate (PbSO4), a Fenton reaction to further leach LFP, and lithium recovery through precipitation with sodium phosphate. Response surface methodology was employed to optimize leaching conditions, achieving a lithium recovery rate of 94.74% with a purity of 98.83%. The study demonstrates that the citric-acid concentration, solid–liquid ratio, temperature, and leaching time significantly impact the metal extraction efficiency. The proposed method not only reduces waste and environmental impact but also offers economic benefits. This research provides a sustainable and cost-effective approach for recycling spent LFP batteries, contributing to a circular economy and resource conservation.

Study on infrared-hot air combined drying characteristics of lithium iron phosphate battery electrode

Experimental analysis of thermal runaway and safety assessment of large-format lithium iron phosphate batteries in a ventilated tunnel

Simultaneous cathode liberation and selective lithium recovery from spent LiFePO4 batteries via sodium persulfate–assisted roasting

A switching-based hybrid estimator with dynamic capacity adaptation for robust state of charge estimation of LiFePO4 batteries

Battery-grade FePO4 recovery from P-rich urine via field-induced electro-Fenton in a compartmental electrolytic cell.

The safety challenges of lithium-ion batteries, particularly in LiFePO4 systems, are rooted not only in the flammability of carbonate-based electrolytes but also in the early-stage exothermic reactions triggered by the breakdown of the solid electrolyte interphase on lithiated graphite. Conventional flame-retardant approaches primarily mitigate combustion in the late stage of thermal runaway yet offer limited protection against these initial interfacial reactions. To fill this critical gap, a two-dimensional electrolyte design was adopted to decouple safety functions from electrochemical behavior. By incorporating three lithiophobic, noncoordinating components─perfluoro-2-methyl-3-pentanone (FK), ethoxy(pentafluoro)cyclotriphosphazene (PFPN), and 1,3,5-trimethyl-1,3,5-tris(3,3,3-trifluoropropyl)cyclotrisiloxane (D3F)─a multifunctional electrolyte, termed RDF, is developed, achieving both robust flame retardancy and protection of the graphite anode. D3F undergoes in situ ring-opening polymerization to reconstruct a siloxane-rich protective interphase, effectively suppressing exothermic reactions, while FK and PFPN cooperatively inhibit combustion in the later stage. This multifunctional protection markedly enhances thermal safety in 4.8 Ah LiFePO4∥Graphite pouch cells subjected to thermal abuse. The RDF electrolyte delays the onset of internal short circuit by nearly 50 min relative to a conventional carbonate electrolyte. Meanwhile, excellent electrochemical performance is retained, with commercial-loading LiFePO4∥Graphite cells maintaining 80.2% capacity after 200 cycles and 1 Ah pouch cells delivering 93% capacity retention over 200 cycles. This work provides a practical and scalable electrolyte design strategy that integrates flame retardancy with interfacial protection, enabling intrinsically safer and high-performance lithium-ion batteries.

A biomimetic polyphenol-gated strategy is proposed to promote interfacial Li+ - selective transport in composite solid electrolytes by chemically bonding the polymer matrix and ceramic nanofibers. The polyphenol interlayers serve as the chemical gates with -OH and -NH groups to immobilize lithium salt anions and carbonyl groups to coordinate Li+, thus lowering the energy barrier and promoting rapid Li+ transport at interface. The assembled Li||LiFePO4 batteries exhibits an impressive capacity of 151.6 mAh g-1 and long lifespan over 600 cycles. Solid-state lithium (Li) batteries offer high-energy density and operational safety but face sluggish Li+ transport in polymer/ceramic composite solid-state electrolytes. Herein, we propose a bioinspired polyphenol-gated interfacial engineering that mimics ion-selective protein channels to enhance Li+-selective transport across the polymer-ceramic interface. Polyphenols such as polydopamine, poly-tannic acid, and poly-gallic acid chemically couple La0.56Li0.33TiO3 ceramic nanofibers and glycidyl polyether matrix. Within this interface, carbonyl groups selectively coordinate Li⁺ and facilitate directional migration. On the other hand, hydroxyl and amino groups immobilize anions via hydrogen bonding. This chemical gating nearly doubles interfacial Li+ concentration and boosts transference number to 0.68. The corresponding Li||LiFePO4 battery exhibits stable cycling over 600 cycles with 85.5% capacity retention at 1 C, while the pouch cell delivers reliable operation under mechanical stress caused by bending and puncturing. This work demonstrates that polyphenol-gated interfaces are essential for promoting selective and efficient cross-phase Li⁺ transport for high-performance solid-state lithium-metal batteries.

ABSTRACT With the rapid development of the electric vehicle industry, the retirement scale of lithium iron phosphate (LiFePO 4 ) batteries has continued to expand, and their efficient and green recycling has become a key issue in resource circulation. This review summarizes the degradation mechanism and regeneration strategies of LiFePO 4 batteries, emphasizing two technical approaches: “Decomposition for regeneration”(Decom‐) and “Repair for regeneration”(Repair). In the decomposition route, valuable metals are recycled and reused through destructive pretreatment combined with pyrometallurgical and hydrometallurgical processes. Conversely, the repair route is based on degradation mechanisms, employing in situ regeneration at the battery or component level, as well as solid‐state sintering, hydrothermal, electrochemical relithiation methods, and modification strategies at the cathode material level. The objective is to recover performance while maintaining the integrity of the complete battery cells or the cathode material structure. This review integrates mechanism analysis with technical comparisons to identify several challenges related to the regeneration technology of spent LiFePO 4 batteries. It anticipates future trends in regeneration technology as well as provides theoretical insights along with practical guidance for the resource recovery and high‐value utilization of retired batteries.

ABSTRACT Increasing environmental pollution and shortage of critical resources call for technologies capable of achieving total resource recovery from waste materials. In this study, high leaching rates of 99.16% for lithium and 97.37% for iron were obtained from spent lithium iron phosphate (LFP) batteries through electrochemical (EC) advanced oxidation processes (EAOPs), and associated leaching mechanism was subsequently investigated. Moreover, residual C, Fe, and P elements in leach residue were directly converted into a P, N‐doped asymmetric single‐atom Fe catalyst (Fe‐CN 3 P), enabled by well‐dispersion of Fe elements and removal of surface passivation layers during leaching. When activated with peroxymonosulfate (PMS), Fe‐CN 3 P catalyst exhibited a pseudo‐first‐order kinetic rate of 10.768 min −1 for bisphenol A (BPA) degradation, which is approximately 2–10 times higher than those of conventional single‐atom catalysts. Based upon experimental and theoretical investigation, the presence of P in the local coordination environment was found to substantially enhance catalytic activity of Fe sites. P incorporation alters the adsorption mode of HSO 5 − on Fe active centres and increases Bader charges in the Fe IV ═O reactive intermediate, thereby improving the capability of Fe to withdraw electrons from the BPA molecules. This study offers new perspectives for synergistically advancing “comprehensive resources recovery” and “waste to treat waste.”

Adaptive sliding mode observer for joint state-of-charge and state-of-health estimation in lithium iron phosphate batteries using a hysteresis-inclusive dual-polarization model

Pilot-scale recovery of high-purity Li2CO3 and FePO4 from real wastewater for sustainable full synthesis of LiFePO4 battery.

Elucidating the electrochemical pathway of deep over-discharge in LiFePO4 batteries: A guideline for optimized pretreatment and material preservation

Thermal runaway behaviors in 18,650 LiFePO4 batteries under high C-rate charge/discharge operations

Recycling lithium iron phosphate (LFP) batteries presents critical economic and environmental challenges because of their low metal value and high energy intensity of conventional metallurgical processes. While direct recycling methods offer a pathway for lithium replenishment, they are often hindered by stringent impurity controls and complex operating conditions that limit scalability. Here, we introduce a controlled overdischarge (COD) protocol as a non-invasive strategy to rejuvenate spent LFP (S-LFP) batteries. COD selectively decomposes the solid-electrolyte interphase, releasing trapped Li+ and reducing Li/Fe antisite defects while simultaneously suppressing copper dissolution. The COD protocol recovers 9.56% of lost capacity and extends lifespan by over 200 cycles. Furthermore, compared to metallurgical recycling, this method markedly lowers greenhouse gas emissions to 168gkg-1 and energy consumption to 3MJkg-1 of feedstock. These findings highlight COD as a sustainable and scalable alternative for S-LFP battery recycling.

Characteristics of gas emission and explosion risk for lithium iron phosphate batteries in a proof-confined chamber: Impact of methane concentration and state of charge

ABSTRACT The enhancement of performance and safety in Li‐ion batteries strongly depends on effective cooling strategies. This study presents a comprehensive, time‐dependent numerical analysis of six alternative configurations of battery thermal designs for an electric racing car. Starting from a benchmark configuration relying on natural convection only, the other configurations incorporate more complex cooling systems, including liquid cooling, forced air convection, and phase change materials (PCM), either individually or in hybrid arrangements. Three‐dimensional computational fluid dynamics (CFD) simulations were performed on a 40‐cell lithium iron phosphate battery pack to evaluate transient temperature evolution under realistic racing operating profiles at ambient temperatures of 20, 25°C and 30°C. To identify the optimal design, a multi‐objective optimization framework is considered and solved through a weighted‐sum scalarization, combining four dimensionless normalized indicators representative of thermal efficiency and structural compactness. The results show that purely passive cooling is insufficient, whereas hybrid liquid–PCM configurations markedly reduce over‐temperatures and improve cell temperature uniformity. An original optimization procedure identifies as optimal a hybrid liquid–PCM solution capable of balancing thermal performance and system compactness while exhibiting robust thermal response over a wide ambient temperature range from 5°C to 35°C. The proposed approach provides a quantitative framework for balancing competing design requirements for high‐performance battery thermal management systems (BTMS).

The significant in-plane heterogeneity of cathode performance in aged lithium iron phosphate batteries: Modeling and mitigation method