以炭黑为碳源制备多孔球形LiFePO_4/C材料

Synthesis of porous spherical LiFePO_4/C using carbon black as carbon source and its performance

以炭黑为碳源,采用喷雾干燥-碳热还原法(SDCTM)制备了多孔隙球形LiFePO4/C正极材料。研究了不同炭黑加入量对LiFePO4/C结晶性能、颗粒形貌、放电比容量和循环稳定性等性能的影响。结果表明:炭黑含量的增加有利于优化一次颗粒形貌,促进LiFePO4的结晶,提高其放电比容量、首次放电效率及容量保持率等电化学性能。当炭黑加入量X=2.5时,球形LiFePO4/C正极材料粒径在10μm左右,其一次颗粒粒径平均在200nm左右,比表面积达4.15m2/g,碳含量12.0%wt。在室温下,0.1C充放电下,放电比容量为131.7mAh/g,首次放电效率为90.8%,30次循环后容量保持率为96.2%。在4C充放电下,仍有65.7mAh/g的可逆比容量,且显示了良好的充放电性能。

Porous spherical LiFePO4/C cathode material was prepared by spraying dry and carbothermal method （SDCTM） using carbon black as carbon cource. The effect of carbon content on crystallinity, morphology, specific capacity and cyclic performance of samples was investigated. The results showed that the carbon dopant optimize morphology of LiFePO4, and improve its crystallinity, electrochemical performance, especially large current charge/discharge behaviors. LiFePO4 /C doped with 12.0% wt carbon was composed of the aggregated spherical particle of 10μm, specific surface area of which was 4.15 m2/g. Its initial discharge capacity was 131.7 mAh/gand its discharge efficiency was 90.8% at room temperature. After 30 cycles, the sample still kept about 96.2% of its initial discharge capacity. Its discharge capacity reached 65.7mAh/g at 4C charge/discharge rate.