文章摘要
郑勇,李建玲,王新东.磷酸铁锂/石墨动力电池的高温衰减机制研究[J].材料导报,2016,30(10):15-18, 32
磷酸铁锂/石墨动力电池的高温衰减机制研究
Capacity Fading Mechanism of LiFePO4/Graphite Power Battery at High Temperature
  
DOI:10.11896/j.issn.1005-023X.2016.10.004
中文关键词: 磷酸铁锂 温度 循环 容量衰退
英文关键词: LiFePO4, temperature, cycling, capacity fading
基金项目:国家科技支撑计划 (2015BAG01B01)
作者单位E-mail
郑勇 北京科技大学冶金与生态工程学院, 北京 100083  
李建玲 北京科技大学冶金与生态工程学院, 北京 100083 franciszheng@163.com,lijianling@ustb.edu.cn 
王新东 北京科技大学冶金与生态工程学院, 北京 100083  
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中文摘要:
      制备了1.1 Ah的18650型LiFePO4/graphite 动力电池并研究了温度对电池循环的作用机制。运用解体与非解体的研究手段系统地分析了电池在循环前后的容量以及正负极材料的形貌、结构与电极容量的变化。结果表明,在经过800周循环后55 ℃下电池的容量衰减显著,循环后电池的Rb与Rct有较为明显的增加。高温下电池的容量衰减主要来自于活性锂离子的损失。对于LiFePO4正极,长周期的循环并未对LiFePO4的结构造成影响,同时电极的容量未见衰减。而对于石墨负极,容量在55 ℃下有12.60%的衰减。在高温循环后负极表面发现了铁元素的沉积。铁元素的沉积加速了石墨电极表面膜的增厚并对电池容量的衰退产生影响。
英文摘要:
      18650 LiFePO4/graphite power batteries with a capacity of 1.1 Ah were assembled, and temperature dependence of capacity fading was studied. The capacity changes of the batteries, combining with electrode morphologies, structures and performances during cycling, were systematically investigated using full battery and post-mortem analysis. Results showed that a serious capacity fading of the as-assembled full battery could be found after cycling at a high temperature of 55 ℃, along with significant increase of Rb and Rct. The loss of active lithium was regarded as the main reason for capacity fading at high temperature. For LiFePO4 cathode, prolonged cycling did not affect the framework structure under various temperatures, while no capacity loss was detected after cycling. For graphite ano-de, however, the experiment confirmed a 12.60% capacity loss for cycled electrode at 55 ℃, and a small amount of Fe deposited on the anode surface, which plays a catalytic role in the growth of the interfacial film at the graphite surface and is responsible for the capacity fading of full battery.
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