| Summary: | 碩士 === 國立臺北科技大學 === 化學工程研究所 === 102 === The anode materials are usually carbon in commercial lithium ion batteries. However, the main drawback for carbonaceous materials has a large irreversible capacity loss , and there is still some safty problem. The crystal size of Li4Ti5O12 does not change during charge and discharge process. Therefore,this material is call zero strain material which has properties of long life and safety. It has the problem of poor rate capability due to its low electronic conductivity.
In studies, we tried to use sol-gel method to synthesize Li4Ti5O12 and searched for optimal synthetic process. First, we change the calcination temperature, heating rate of calcination,and calcination duration in order to synthesis, and find the best conditions. Second, the same proportion of different metal ion doped on Li4Ti5O12, and electrochemical performance analysis.
The result shows that calcination temperature must reach 800℃ maintaining 14 hours and the rate is 4℃/min to keep better crystallinity. The discharge capacity of Li4Ti5O12 is 152.2 mAh/g and 58mAh/g at 0.1C and 10C. The discharge capacity of Li4Al0.05Ti4.95O12 is 157 mAh/g and 79 mAh/g at 0.1 C and 10 C. And the discharge capacity of Li4La0.05Ti4.95O12 is 160.2 mAh/g and 112.6 mAh/g at 0.1 C and 10 C. In addition the discharge capacity of Li4Ce0.05Ti4.95O12 is 165.6 mAh/g and 122.8 mAh/g at 0.1 C and 10 C.
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