科研之友
微信
新浪微博
Facebook
分享链接
摘要
Carbon coating is an important technique used to improve the electrochemical performance of many electrode materials in lithium-ion batteries. In the present work, Li4Ti5O12 was selected as the probe material and a series of carbon-coated Li4Ti5O12 samples was prepared to discuss the effects of graphitization and thickness of the coated carbon layer on its rate capability for lithium-ion intercalation. The apparent diffusion coefficient (D-Li) and rate capability were studied by cyclic voltammetry experiments using a powder microelectrode. The results show that a higher carbon coating temperature could promote the graphitization of the surface carbon, thus enhancing the electronic conductivity of the electrodes while hindering the lithium-ion diffusion. The thickness of carbon layer is demonstrated to have a major influence on ion diffusion while slightly affecting the electronic conductivity. Considering both the electronic conductivity and ion diffusion in the carbon layer, an optimal condition for carbon coating to achieve a good rate capability is determined to be performed at 800 degrees C with a thickness of ca. 5 nm.
- 出版日期2011
- 单位复旦大学
