Large-Scale Synthesis of High Energy Thermal Battery Cathode Ni_0.5Co_0.5S₂ by a Simple Sintering Technique

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 NiS₂ and Co₃S₄ are devoted to the synthesis of single-phase Ni_0.5Co_0.5S₂. Because the reaction from NiS₂ and Co₃S₄ to Ni_0.5Co_0.5S₂ goes through a lower energy, it thermodynamically contributes to achieving a single-phase structure. Thus, single-phase Ni_0.5Co_0.5S₂ 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-CoS₂. Ni_0.5Co_0.5S₂ 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 NiS₂ (566 mAh·g^-1) and CoS₂ (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.