Effects of High-Rate Cycling on the Bulk Internal Pressure Rise and Capacity Degradation of Commercial LiCoO2 Cells
Effects of High-Rate Cycling on the Bulk Internal Pressure Rise and Capacity Degradation of Commercial LiCoO2 Cells
复制标题
高倍率循环对商用 LiCoO2 电池整体内压上升和容量下降的影响
DOI：
--
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Fuqiang Liu
中科院分区：
文献类型：
--
作者：
Anthony F. Matasso;D. Wong;D. Wetz;Fuqiang Liu
具有相同LiCoO 2/石墨电极的商业锂离子电池在高速率放电、高速率充电以及高速率充电和放电两者下循环，直到容量达到60%。定期进行基线表征测试，包括内部压力，放电容量和电化学阻抗谱（EIS）。在所有三种条件下，在压力升高和容量衰减中都可以看到一个双线性行为，早期抛物线依赖于循环次数的平方根，然后过渡到线性依赖于循环次数。在所有测试的细胞中，发现了指示两个变量之间非常强的统计学显著关系的直接相关性。CO，CO2，CH 4，C2 H6，和C3 H8的鉴定与后循环气相色谱分析表明与痕量杂质和电解质的减少反应。SEM分析鉴定了阳极表面上的过量钝化层，推测是由于阳极表面处的电解质的还原，而阴极证明随着循环没有显著变化。EIS分析表明，RCT在早期阶段的变化很小，但低频循环发生了相当大的变化，这是由于
Commercial lithium-ion cells with the same LiCoO2/graphite electrodes were cycled at high-rate discharge, high-rate charge, and both high-rate charge and discharge until the capacity reached 60%. Periodic baseline characterization tests were performed including internal pressure, discharge capacity, and electrochemical impedance spectroscopy (EIS). A paralinear behavior with an early parabolic dependence on the square root of the cycle number, followed by a transition into a linear dependence on cycle number was seen in both the pressure rise and capacity fade in all three conditions. A direct correlation indicating a very strong, statistically significant relationship between the two variables was identified in all the cells tested. CO, CO2 ,C H4 ,C 2H6 ,a nd C3H8 were identified with post cycling gas-chromatography analysis indicating reactions with trace impurities and a reduction of the electrolyte. SEM analysis identified an excessive passivation layer on the surface of the anode presumably due to the reduction of electrolyte at the anode surface, while the cathode demonstrated no significant change with cycling. EIS analysis indicated an minimal change in RCT in the early stages, however the low frequency semicircle underwent considerable change due to a stronger contribution of the