Large-Scale Synthesis of High Energy Thermal Battery Cathode Ni<sub>0.5</sub>Co<sub>0.5</sub>S<sub>2</sub> by a Simple Sintering Technique
Xuefeng Chen, Chengcheng Zhang, Bin Yao, Licheng Tang, Zaifang Yuan, Jiajun Zhu, Wulin Yang, Lingping Zhou, Licai Fu
Abstract
With the synergies of multiple elements, bimetallic sulfides exhibit excellent performance as splendid electrode materials and effective catalysts. However, large-scale synthesis of high-performance single-phase multicomponent sulfides has always been a challenge. Based on thermodynamic calculations, the intermediate phases NiS 2 and Co 3 S 4 are devoted to the synthesis of single-phase Ni 0.5 Co 0.5 S 2 . Because the reaction from NiS 2 and Co 3 S 4 to Ni 0.5 Co 0.5 S 2 goes through a lower energy, it thermodynamically contributes to achieving a single-phase structure. Thus, single-phase Ni 0.5 Co 0.5 S 2 can be simply and quickly prepared by two-step sintering and successfully scalable for mass production. This technique can extend to the whole ingredients Ni 1– x Co x S 2 . Ni 0.5 Co 0.5 S 2 demonstrates excellent thermal stability and good conductivity. It delivers a specific capacity of 671 mAh·g –1 and a specific energy of 1173 Wh·kg –1 when applied to a thermal battery cathode, which are increased by 18.6% and 25.0%, respectively, compared to pristine NiS 2 (566 mAh·g –1 ) and CoS 2 (537 mAh·g –1 ). This work proposes an innovative sintering method, which is applicable for cost-efficient and large-scale synthesis of single-phase multicomponent sulfides.