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采用球磨法将Sn-Co合金与石墨复合制备了Sn-Co/石墨复合材料,并对其进行热处理,研究了热处理温度对复合材料结构和电化学性能的影响。结果表明,Sn-Co/石墨复合材料由Co Sn相和石墨组成,Sn-Co合金一部分嵌入石墨颗粒内部,一部分吸附在石墨颗粒表面。电化学测试表明,Sn-Co/石墨复合材料兼具高容量和长循环寿命的优点,首次放电容量和库伦效率分别为349 m A·h/g和81.3%,经过25次循环后的容量保持率为88.3%。热处理导致Sn-Co合金的晶粒长大和Co3Sn2新相的出现,同时降低了复合材料的比表面积。当热处理温度为500℃时,首次放电容量和库伦效率分别为362 m A·h/g和83.6%,经过25次循环后的容量保持率达92.8%,表现出良好的结构稳定性。
The Sn-Co / graphite composites were prepared by ball milling and the Sn-Co / graphite composites were prepared and heat treated. The effects of heat treatment temperature on the structure and electrochemical properties of the composites were investigated. The results show that Sn-Co / graphite composites consist of Co-Sn phase and graphite. Part of Sn-Co alloy is embedded in graphite particles and partly adsorbed on the surface of graphite particles. Electrochemical tests show that the Sn-Co / graphite composite has the advantages of high capacity and long cycle life. The first discharge capacity and coulombic efficiency are 349 m A · h / g and 81.3%, respectively. After 25 cycles, the capacity retention The rate was 88.3%. Heat treatment results in the grain growth of Sn-Co alloy and the appearance of a new phase of Co3Sn2, while reducing the specific surface area of the composite. When the heat treatment temperature is 500 ℃, the first discharge capacity and coulombic efficiency are 362 m A · h / g and 83.6%, respectively. After 25 cycles, the capacity retention rate reaches 92.8%, showing good structural stability.