One-step vapor-pressured induced synthesis of spherical-like Co ₉S ₈/N, S-codoped carbon nanocomposites with superior rate capability as lithium-ion-battery anode

摘要

As high theoretical capacity and excellent electrical conductivity, Co_(9)S_(8)as a promising electrode material in lithium-ion batteries (LIBs) has attracted wide attention. In the present work, a simple vaporpressured induced route is developed for fabricating spherical-like Co_(9)S_(8)/N, S-codoped carbon nanocomposites (Co_(9)S_(8)/NSC), in which Co_(9)S_(8)nanoparticles with an average size of 100 nm are encapsulated into N, S-codoped carbon matrix, by pyrolysis of mixture of cobalt isooctanoate dissolved into dimethylformamide and thiourea in a sealed vessel for the first time. As anode for LIBs, the Co_(9)S_(8)/NSC shows an excellent reversible capacity, a superior rate performance, and a long cycling stability. For example, a high capacity of 975.3 mA h g~(-1)can be achieved after 100 cycles at 0.1 A g~(-1). When cycled at 1 A g~(-1), it also maintains a high specific capacity of 791.5 mA h g~(-1)after 1000 cycles. Besides, it also shows a superior rate performance (329.8 mAh g~(-1)at 20 A g~(-1)). Such superior performances may arise from its structural advantages that the smaller Co_(9)S_(8)nanoparticles encapsulated into N, S-codoped carbon could enhance active sites, electrical conductivity, and structural stability.