中间相炭微球的粒径对其结构和性能的影响

Effects of particle size on structure and characteristics of meso-carbon microbeads

采用X射线衍射、粒径分析、扫描电子显微镜、BET比表面积分析及电化学方法研究了粒径对中间相炭微球结构和性能的影响。研究结果表明随着粒径的增加,中间相炭微球的堆积密度增大,比表面积减小;中间相炭微球电极的充电容量和不可逆容量减小,可逆容量与首次充放电效率增加;以中间相炭微球为负极制成063448型锂离子电池的放电容量随着中间相炭微球平均粒径的增大而增加,不可逆容量减少;以平均粒径为19.09μm的中间相炭微球为负极制成的电池放电容量为838mA·h,首次充放电效率为87.29%,循环100次后的容量保持率为92.4%。

The effects of particle size on structure and characteristics of meso-carbon microbead (MCMB) were investigated. The MCMB was characterized by X-ray diffraction, particle size analysis, Brunauer-Emmer-Teller (BET) specific surface area and electrochemical measurements. The MCMB powder with larger average particle size has higher tap density and smaller BET surface area. As the average particle size increases, charge capacity and irreversible capacity of the MCMB anode reduce, while the reversible capacity and initial charge/discharge efficiency rise. According to the electrochemical measurements of 063448 type lithium ion batteries, the batteries with larger size MCMB anodes have higher discharge capacity and smaller irreversible capacity. Using the MCMB with average particle size of 19.09 μm as anodes, the batteries have high capacity of 838 mA·h, large initial charge/discharge efficiency of 87.29% and high capacity retention ratio of 92.35% after 100 cycles.