Preparation and electrochemical properties of CoS2 cathode materials

CoS2 were synthesized under hydrothermal condition using cobaltous chloride hexahydrate (CoCl2·6H2O) and thiourea (CS(NH2)2) as precursors at different pH values. The phase composition, morphology, thermal stability and electrochemical properties of CoS2 cathode material were characterized and tested. The results show that there are two kinds of mechanisms about the CoS2 synthesis in acid and alkali environments, single-phase pyrite CoS2 with spherical-like and irregular block morphology can be obtained in pH=5 and pH=10, respectively, the decomposition temperatures are 650 and 610 , respectively. Then thermal batteries were assembled using the CoS2 as positive active materials. When batteries were discharged in 100 mA/cm2 current density, the first discharge platform voltage and specific capacities were basically the same of the two kinds CoS2 cathode materials. As the discharge current density increasing in 800 mA/cm2, the specific capacity of spherical-like CoS2 improved 9.65% than the block CoS2 and it had higher discharge voltage and smaller internal resistance features than the latter. ©, 2015, Chinese Ceramic Society. All right reserved.