Research On Silicon/Carbon Composite Materials For Lithium Ion Battery

This paper summarized the actual research situation of the Li-ion battery, and particularly reviewed the actual research status of silicon-based negative material of lithium ion battery. Based on summarizing the actual research status, developing prospects, and the characteristic of different ways in preparation for silicon based composite, three ways were chosen , which was pyrolysis for Si- Phenolic resin prolyzed carbon material, using different catalyzer to prepare for Si-O network coated silicon and carbon complex composite, easily chemical and deoxidizing reaction for super tiny metals mixed silicon and carbon complescomposite. Through XRD SEM testing, surface configuration, composition and structure of the products were studied. Through the charge/discharge test, CV experiments, EIS analysis, the electrochemical performance were investigated.Si- Phenolic resin pyrolyzed carbon material was made by pyrogenation method. The prepared temperature is 700℃. It is found that Si-C(PR)=3:7(weight ratio) has the best performance, whose first charge capacity is 394.7mAh·g^-1, and the first cycle efficiency is 50%. When adding 20% graphite (weight ratio) to the received material, its first charge capacity is 529.1mAh·g^-1, and the first cycle efficiency is 62%. After 30 time cycles, the reversible capacity is 135mAh·g^-1. To improve the performance of the material just referring, mechanical milling is used before high temperature pyrogenation. It can increase reversible capacity of 50mAh·g^-1's left or right. Adding a little amount of Zn, the reversible capacity is around 214mAh·g^-1 after 30cycles. After heat treatment of the electrode, reversible capacity attains as high as 260mAh·g^-1 in the 30th cycles.Si-O network coated silicon and carbon complex composites are made in different catalysts, which are acid catalyst or alkaline catalyst. The different catalysing situations lead to different configuration of Si-O network, which affects the electrochemical performance of the material. The material which is reacted in the condition of acid catalyst has a first charge capacity of 177.9mAh·g^-1 and charge and discharge efficiency of 68%. The efficiency of the sample made in alkaline catalyst is 79% and a first charge capacity of 201.2mAh·g^-1. The material which is reacted in the condition of alkaline catalyst and high temperature has a good first charge and...