N、B共掺杂空心碳球结构设计及其锂硫电池性能研究

N,B co-doped hollow carbon sphere architectural design and its performance in lithium sulfur batteries

采用二氧化硅包覆限域碳化的方法,制备N、B共掺杂空心纳米碳球。碳球直径为245 nm,空腔内径为165 nm,比表面积为666 m^(2)/g。与非限域碳化空心碳球对比,限域碳化可以有效扩大碳球空腔直径。以空心碳球为载体制备碳硫复合正极材料,碳球的大空腔结构可以提高锂硫电池硫正极中单质硫的利用率和循环稳定性,复合材料0.1 C放电比容量809 mAh/g;1.0 C初始放电比容量716 mAh/g,循环300次后比容量551 mAh/g,每次容量损失率0.077%。同时,碳球的多孔壁层结构可以提高锂离子的传输动力学,材料表现出良好的倍率性能,5 C放电比容量为423 mAh/g。

By confined carbonization with SiO_(2) coating layer,N,B-codoped hollow carbon sphere was obtained.The diameter of carbon nanosphere is 245 nm with hollow core interior-diameter of 165 nm,and its specific surface area is 666 m^(2)/g.Confined carbonization can enlarge the interiordiameter of the carbon sphere.Using the hollow sphere as sulfur host,carbon/sulfur cathode materials was synthesized.The large interior-hollow space of the sphere could effectively improve the utilization of sulfur and the cycle performance of lithium-sulfur batteries.At 0.1 C discharge rate,specific capacity is 809 mAh/g,and at 1 C,the initial specific capacity is 716 mA h/g,and after 300 cycles,the reversible specific capacity is 551 mA h/g,with a capacity decay of only 0.077%per cycle.The nanoporous carbon sphere wall,can provide the fast distribution of Li+,improving the reaction kinetics of lithium-sulfur batteries,the composites present excellent high rate performance at 5 C with specific capacity of 423 mAh/g.