LiCoO_2的电化学性能和过充特性研究

Study on the electrochemical performance and overcharge characteristics of LiCoO_2

以两种具有不同粒径、比表面积和振实密度的LiCoO2为正极材料,组装053048型锂离子电池,研究其电化学性能、1.0C/12 V过充特性及其过充机理。结果表明:LiCoO2比表面积对过充测试结果影响很大;比表面大、细颗粒多的LiCoO2,过充测试时产生较多的活性反应位置,导致电池发生热失控、爆炸。正极材料的晶体结构和振实密度对过充特性也有影响。D50小的LiCoO2经过100次循环后,容量保持率>95%,3.6 V平台>82%,表现出良好的电化学性能。

The electrochemical performance, 1.0 C/12 V overcharge characteristics and overcharge mechanism of 053048 type Li-ion battery based on LiCoO2 cathode material with different grain sizes, specific surface areas and tap densities were studied. The results showed that the specific surface area of LiCoO2 played an important role on the overcharge test results. During the overcharge, the bigger specific surface area and more tiny grains of LiCoO2 provided more active reaction sites, brought on the thermal run-away and explosion of the battery. The crystal structure and tap density of the cathode material had the effect on overcharge characteristics. The LiCoO2 with small D50 had a big capacity retention （ 〉 95%） and high 3.6 V capacity （ 〉 82%） after 100 cycles, displaying good electrochemical performance.