Ethylenediamine-assisted synthesis of microsized cobalt sulfide as advanced anode materials for sodium ion batteries
Xue Liu, Hua Ma, Qiongzhen Liu, Yuedan Wang, Zhentan Lu, Mufang Li, Jianbin，Wang, Dong Wang
Microsized cobalt sulfide is prepared via a solvothermal method in ethylenediamine solution by using CoCl2·6H2O as cobalt resource and thioacetamide as the sulfiding reagent. By varying the reaction parameters, CoS-24 and CoS-48 are obtained at 180 °C for 24 h and 48 h, respectively. Scanning electron microscopy and transmission electron microscopy images reveal that the microstructures are both assembled by nanosheets with width in the range of 130-160 nm and thickness of 30-50 nm. When used in SIBs, the more dispersed CoS-48 electrode exhibits superior sodium storage performances than that of CoS-24. For CoS-48, a specific capacity of 753 mAh g-1 is delivered at the current density of 100 mA g-1 in the potential window of 0.1-3.0 V. Moreover, 392 mAh g-1 can still be maintained at the current density of 1000 mA g-1 after 200 cycles, corresponding to 80% retention. These results demonstrate the potential of the carbon-free cobalt sulfide as high performance anode materials for energy storage.
