Microwave- or conventional–hydrothermal synthesis of Co-based materials for electrochemical energy storage

Crystalline Co3O4 and Co(OH)2 were synthesized using Co(NO3)2 as a precursor by conventional–hydrothermal and microwave–hydrothermal routes, respectively. The Co3O4 phase showed cubic morphologies while the β-Co(OH)2 phase exhibited plate-like shapes. The electrochemical performances of Co3O4 and Co(OH)2 phases were evaluated as electrode materials for lithium-ion battery anodes, cathodes and supercapacitors. Both Co3O4 and Co(OH)2 phases showed pseudocapacitive performances in Li2SO4 and KOH electrolytes. The Co3O4 and Co(OH)2 phases were found to be more promising as anodes than as cathodes in lithium-ion batteries. The Co(OH)2 electrodes showed higher specific capacitances than those of Co3O4 materials.