Koichi Takizawa

Behavior of CoO-NiO Solid Solution in Molten Carbonate

Focusing on the fact that cobalt oxide (CoO) and nickel oxide (NiO) form a good solid solution, we examined the behavior of this material in molten carbonate in order to evaluate the feasibility of the NiO cathode coated with stable lithium cobaltite (LiCoO 2 ). In the molten carbonate at 650°C, the CoO-NiO solid solution created LiCoO 2 on its surface. The solubility measurement results indicated a suppression of the Ni dissolution which seems attributable to the LiCoO 2 coating. However, during the long-range immersion treatment, the LiCoO 2 layer on the solid solution surface grew and partially broke away from the solid solution matrix. In the powder-based immersion test, it was also verified that LiCoO 2 particles grew to relatively large ones. For use as an alternative cathode material, it is necessary to suppress the crystal growth of the LiCoO 2 coating layer.