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摘要: 结合磷酸铁锂纳米化,并利用碳纳米管良好的导电性和大长径比等优良特性,采用喷雾干燥方法制备出碳纳米管原位复合磷酸铁锂正极材料。碳纳米管在材料合成过程中均匀分散在活性物质中,形成连续贯通的三维导电网络,这种结构可显著提高磷酸铁锂正极材料的电子导电性和锂离子的扩散速率。所得材料具有良好的大电流放电特性,在50 C 充放电时, 比容量达到99mAh / g;同时该材料也具有优异的循环性能,在10 C 大电流充放电的情况下,450 次循环后容量保持率仍大于 90%Abstract: A hybrid cathode material for high rate lithium ion batteries was prepared by ball-milling and spray drying a slurry containing LiFePO4 nanoparticles, glucose and carbon nanotubes (CNTs) in water, followed by pyrolysis at 600 for 6 h under a gas mixture of 5% H2 in Ar. CNTs with a large aspect ratio form a continuous conductive network connecting the LiFePO4 nanoparticles and amorphous carbon, which significantly reduces the electrical resistance of the cathode. The hybrid material can deliver a specific capacity of 99 mAh / g at a 50 C charge / discharge rate. An excellent cycling performance was also demonstrated, with a capacity loss of less than 10% after 450 cycles at a 10 C rate.
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Key words:
- LiFePO4 /
- Carbon nanotubes /
- Conductive framework /
- High rate cathode materials
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