Research On Two Anode Materials For Lithium-ion Batteries

Lithium-ion batteries are most promising high power secondary batteries due to its advantages of higher energy density, more safety, longer lifetimes and no pollution. In order to satisfy the demand of Lithium-ion batteries development, it is necessary for people to find electrode material with high capacity and better safe. And it is a research topic to find new type anode material to replace traditional carbon materials. The paper is mainly focused on the preliminary study on two aspects of anode material.The cycle and rate performance of the cyclindrical cell with Si/C and graphite anode were studied in this paper. Also the problem occurred in application as well as the failure mechanism was analyzed. Capacity retainment was keeping 69.5% of the initial capacity after 200 cycles. And discharge platform was a bit lower than that of graphite anode. The reason of fast capacity fading mainly are the electrode active material felling off due to electrode volume swelling leading to worse electric contact that result in greater polarization and less capacity; SEI film was destroyed and followed gradually electrolyte decomposition which result in thicker interface film and greater impedance. And the main reason for the capacity loss is the Li⁺ ion can not be fully deserted due to internal structure of the material.The solid phase synthesize method of Li₄Ti₅O₁₂ and its performance was studied in this paper. The condition of different lithium resources, different calcining temperature and time, and with or without dispersing agent and so on were studied. The best synthesis experiment condition was optimized. There is steady discharging platform around 1.55V(vs Li/Li⁺) of Li₄Ti₅O₁₂ samples where charging platform was a bit higher than the discharging platform. The first specific discharging capacity is 146mAh/g. It exhibit steady cycle performance. The material is a higher safe and longer lifetimes lithium ion anode material.