| Summary: | 碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 93 === The purpose of this research was to improve characters and surface structure of graphite by carbon coating process to enhance the performance of lithium ion secondary batteries anode materials. This study used graphite prepared by spherical graphite. With phenol resin pyrolysis at high temperature, amorphous carbon was coated on the graphite surface to increase the graphite layer stability. When the added phenol resin amounts approaches 45wt%, the electrochemical quality shows the higher reversible capacities up to 380mAh/g and higher stability after several cycles. This result enhances the performance of the lithium ion batteries.
Phenol resin was pyrolysized to hard carbon by covering on the graphite surface after heat treatment at 800°Cand 1100°C. It induces the decreasing of graphite crystallization and the increasing of agglomeration phenomenon among the particles as analyzed by using XRD and SEM. When temperature is raised to 1100°C, it shows the better characters of reversible capacities, stability and columbic efficiency than that heated at 800°C.
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