Thermal-overdischarge coupling induced aging mechanisms in LiFePO4 batteries: insights from multi-scale electrochemical and material diagnostics

IF 11 1区工程技术 Q1 ENERGY & FUELS

Applied Energy Pub Date : 2025-10-07 DOI:10.1016/j.apenergy.2025.126870

Rui Tang , Yuelei Xu , Jinyang Dong , Qi Shi , Kang Yan , Yibiao Guan , Yun Lu , Yu Su , Jinzhong Liu , Fangze Zhao , Yi Jin , Ning Li , Yuefeng Su , Feng Wu , Lai Chen

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引用次数: 0

Abstract

This study deciphers aging mechanisms in lithium iron phosphate (LiFePO₄) batteries under coupled thermal-electrochemical stresses using a multi-scale approach. Industrial-grade LiFePO₄/graphite pouch cells underwent accelerated aging across orthogonal temperature (25/45/65 °C) and discharge cut-off voltage (2.5/1.0/0.5 V) conditions. Integrating electrochemical diagnostics (DCIR, EIS, IC/DV) with post-mortem characterization (SEM/TEM/XRD/ToF-SIMS/μXRF) reveals that: (1) Elevated temperatures amplify lithium loss and SEI instability; (2) Deep over-discharge (≤1.0 V) triggers anode degradation via graphite structural collapse, copper dissolution, and SEI rupture; (3) Coupled stresses induce synergistic failure—manifested by DCIR transitions from linear to exponential growth—correlated microscopically with dead lithium accumulation, metal deposition percolation, and interfacial collapse; (4) Extreme conditions (65 °C/0.5 V) provoke atypical mechanisms including cathode FePO₄ segregation and copper migration. The work establishes DCIR inflection as a non-destructive marker for failure-stage transition and provides fundamental insights into stress-coupled degradation pathways, advancing predictive models for LiFePO₄ battery durability in energy storage systems.

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LiFePO4电池热过放电耦合诱发老化机制：来自多尺度电化学和材料诊断的见解

本研究采用多尺度方法解读了在耦合热电化学应力下磷酸铁锂（LiFePO4）电池的老化机制。工业级LiFePO4/石墨袋电池在正交温度（25/45/65°C）和放电截止电压（2.5/1.0/0.5 V）条件下加速老化。电化学诊断（DCIR， EIS, IC/DV）与死后表征（SEM/TEM/XRD/ToF-SIMS/μXRF）相结合，发现：(1)高温放大了锂的损失和SEI的不稳定性；(2)深度过放电（≤1.0 V）通过石墨结构崩塌、铜溶解、SEI破裂等方式引发阳极降解；(3)耦合应力诱发协同破坏，表现为DCIR由线性增长向指数增长转变，微观上与死锂积累、金属沉积渗透和界面崩溃相关；(4)极端条件（65°C/0.5 V）引发非典型机制，包括阴极FePO4偏析和铜迁移。该研究建立了DCIR拐点作为故障阶段过渡的非破坏性标志，并为应力耦合降解途径提供了基本见解，推进了储能系统中LiFePO4电池耐久性的预测模型。

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来源期刊

Applied Energy 工程技术-工程：化工

CiteScore

21.20

自引率

10.70%

发文量

1830

审稿时长

41 days

期刊介绍： Applied Energy serves as a platform for sharing innovations, research, development, and demonstrations in energy conversion, conservation, and sustainable energy systems. The journal covers topics such as optimal energy resource use, environmental pollutant mitigation, and energy process analysis. It welcomes original papers, review articles, technical notes, and letters to the editor. Authors are encouraged to submit manuscripts that bridge the gap between research, development, and implementation. The journal addresses a wide spectrum of topics, including fossil and renewable energy technologies, energy economics, and environmental impacts. Applied Energy also explores modeling and forecasting, conservation strategies, and the social and economic implications of energy policies, including climate change mitigation. It is complemented by the open-access journal Advances in Applied Energy.