| Summary: | 碩士 === 國立虎尾科技大學 === 材料科學與綠色能源工程研究所 === 102 === In this thesis, two new Cathode materials has been developed (Li2Mn0.5Fe0.5SiO4 and Li2Mn0.2Fe0.8SiO4).The characterics of material and its application to battery are also studied . The advantages of these silicate cathode materials are high safety, low cost, compared with no environmental pollution, and high theoretical energy density. However there are several drawbacks need to improve, including low electronic conductivity and low ion diffusion rate respectively,limit the applications of these materials.
In this study, the Li2Fe1-xMnxSiO4/C composite cathode materials is prepared by sol-gel method. The XRD shows a stable crystal structure of Li2Fe1-xMnxSiO4 and the elemental analysis shows that 40% of pitch coated carbon significantly improves, the conductivity of the material. Raman spectroscopy, Confirms a higly graphitization of the pitch has been coated a cathod surface.The battery performance measured results show that the pith coated cathode material (Li2Fe1-xMnxSiO4/C) can be charged and discharged at the rate of 0.1C.The discharge capacity in the first cycle is 183mAh/g. The discharge capacity retention after 30 cycles presents 85%,which demonstrates excellent cycle life . These cathode materials are highly considerable to the future applications.
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