Temperature dependent ageing mechanisms in Lithium-ion batteries - A Post-Mortem study
Temperature dependent ageing mechanisms in Lithium-ion batteries - A Post-Mortem study
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DOI：
10.1016/j.jpowsour.2014.03.112
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发表时间：
2014-09-15
影响因子：
9.2
通讯作者：
Wohlfahrt-Mehrens, Margret
中科院分区：
文献类型：
--
作者：
Waldmann, Thomas;Wilka, Marcel;Wohlfahrt-Mehrens, Margret
用电化学方法和尸检分析定量研究了温度在-20℃~70℃范围内对循环锂离子电池老化行为的影响。试验系统采用了以LixNi1/3Mn1/3Co1/3O2/LiyMn2O4为混合正极，石墨/碳阳极为正极的商用18650高功率电池。电池以1摄氏度的速度循环，直到放电容量降至初始容量的80%以下。有趣的是，Arrhenius曲线表明，在-20摄氏度到25摄氏度和25摄氏度到70摄氏度的范围内有两种不同的老化机制。在25摄氏度以下，老化速度随着温度的降低而增加，而在25摄氏度以上，老化速度随着温度的升高而加快。通过扫描电子显微镜、能量色散X射线分析、电感耦合等离子体、电极厚度测量和拆解后的X射线衍射仪对老化的18650细胞进行了检测，以进一步了解降解的化学原因。以参比电极为模型系统，在气囊电池中组装电极，研究了不同温度对电极极化的影响。我们发现，T<；25℃的主要老化机制是电镀锂，而T>；25℃的阴极表现出退化，阳极将越来越多地被SEI层覆盖。(C)2014爱思唯尔B.V.保留所有权利。
The effects of temperatures in the range of -20 degrees C to 70 degrees C on the ageing behaviour of cycled Lithium-ion batteries are investigated quantitatively by electrochemical methods and Post-Mortem analysis. Commercial 18650-type high-power cells with a LixNi1/3Mn1/3Co1/3O2/LiyMn2O4 blend cathode and graphite/carbon anode were used as test system. The cells were cycled at a rate of 1 degrees C until the discharge capacity falls below 80% of the initial capacity. Interestingly, an Arrhenius plot indicates two different ageing mechanisms for the ranges of -20 degrees C to 25 degrees C and 25 degrees C to 70 degrees C. Below 25 degrees C, the ageing rates increase with decreasing temperature, while above 25 degrees C ageing is accelerated with increasing temperature. The aged 18650 cells are inspected via scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), inductively coupled plasma (ICP), measurements of electrode thickness and X-ray diffraction (XRD) after disassembly to learn more about the chemical reasons of the degradation. The effect of different temperatures on the electrode polarizations are evaluated by assembling electrodes in pouch cells with reference electrode as a model system. We find that the dominating ageing mechanism for T < 25 degrees C is Lithium plating, while for T > 25 degrees C the cathodes show degeneration and the anodes will be increasingly covered by SEI layers. (C) 2014 Elsevier B.V. All rights reserved.