Preparation And Electrochemical Properties Of Carbon Modifying Carbon/Graphite Core-Shell Structure As Elecrode Material For Lithium-Ion Batteries

How to select anode materials is the dominated factor which controls applications of lithium-ion batteries. Graphite is in popular use nowadays, but considering the fact that graphite has high selectivity for electrolyte, especially in PC electrolyte, solvated lithium ion insert electrode which will lead electrolyte’s decomposing, resulting in the decrease of cyclic performance of battery. And carbon black has high capacity, but its capacity per unit volume is low, which restraint its application in Miniaturization device. In order to solve these problems, we do some surface modification with these two carbon anode materials.In order to prepare composite, Graphite and carbon black are selected as matrix, and pitch and phenolic resin are selected as the coating material. By SEM we characterize the morphology of pitch modifying graphite and phenolic resin modifying carbon black composite. By XRD we characterize the structure of pitch modifying graphite, the structure of acid treated carbon black, and the structure of phenolic resin modifying carbon black. In addition we investigate the electrochemical properties of composites. The results are as follows:(1) Taking sphere graphite and none sphere graphite into account, along with the pitch addition increasing, pitch on graphite increases and composites remain the structure the same as graphite. Taking phenolic resin modifying carbon black composite into account,29002transfer to angel increasing direction, indicating that002lattice plane decreases。(2) Taking none sphere graphite’s composites into account, The sample whose pitch mass addition is31.2%of graphite has the best electrochemical property. Its first reversible capacity is375.1mAh/g. After50cycles, its charge capacity still remains386.4mAh/g.(3) Taking sphere graphite’s composites into account, The sample whose pitch mass addition is17.3%of graphite has the best electrochemical property. Its first reversible capacity is325.9mAh/g. After50cycles, its charge capacity still remains349.5mAh/g.(4) Among those carbon black to make composites, the sample whose mass ratio of phenolic resin and modifying carbon black is10%, carbonized at900℃, its first cycle reversible capacity is372mAh/g, the50th cycle capacity remains322mAh/g.