储能锂离子电池高温循环衰减机制分析

Analysis of high temperature cycle attenuation mechanism of energy storage lithium ion battery

研究了叠片型相碳微球/石墨//LiNi0.3Co0.3Mn0.3O2储能用锂离子电池高温循环电化学性能和容量衰减机理。运用恒流恒压模式进行充放电测试,利用微分容量分析正极和负极电位与容量变化关系,电化学交流阻抗谱分析电池、正负极在循环过程阻抗变化趋势,扫描电子显微镜(SEM)和X射线粉末衍射光谱测试分析(XRD)循环前后正极与负极材料形貌和结构变化。结果表明,电池容量的衰减主要来自于电池极化损失,而极化损失与循环过程负极SEI膜增厚和晶格缩小导致扩散动力学能力下降有关。本研究对储能锂离子电池体系性能改善提供实验基础和理论支持。

The cycle performance and capacity decay mechanism of mesocarbon microbeads/graphite//LiNi0.3Co0.3-Mn0.3O2 energy storage lithium ion batteries at high temperature were investigated.The cycle performance test was carried by galvanostatic charge-discharge protocol.The relations between the potential and capacity for electrodes were analyzed with the differential capacity method.The electrochemistry properties of batteries and electrodes after different cycles were studied by EIS.The morphology and crystal structure of electrodes before and after cycles test were characterized by SEM and XRD.The results show that the capacity loss is attributed to the increased polarization resistance of the electrodes,which is related to the decrease of the diffusion kinetics due to the thickening of the negative SEI film and the shrinkage of the lattice during the cycling process.This study provides experimental basis and theoretical support for improving the performance of lithium ion battery.