Preparation of NiS[sub 2] Using Spark-Plasma-Sintering Process and Its Electrochemical Properties

Single-phase , which was hardly prepared by conventional processes such as mechanical milling or precipitation reaction, was prepared using the spark plasma sintering (SPS) process. Using porous Ni (porosity 95%) as a starting material, similar-shaped porous (porosity 89%), containing trace amounts (ca. 3%) of NiS, and finally single-phase powder were obtained by the SPS process. The electrochemical tests demonstrated that the present samples showed the initial discharge capacity of ca. , which was of the theoretical value. The capacity retention after was ca. 19%, and such rapid degradation was mainly attributable to the irreversibility of the Li extraction from the lithiated (discharged) electrodes and the electrical disconnections among the active materials, carbon powders, and/or current collectors.