Crystalline Co 3 O 4 and Co(OH) 2 were synthesized using Co(NO 3 ) 2 as a precursor by conventional–hydrothermal and microwave–hydrothermal routes, respectively. The Co 3 O 4 phase showed cubic morphologies while the β-Co(OH) 2 phase exhibited plate-like shapes. The electrochemical performances of Co 3 O 4 and Co(OH) 2 phases were evaluated as electrode materials for lithium-ion battery anodes, cathodes and supercapacitors. Both Co 3 O 4 and Co(OH) 2 phases showed pseudocapacitive performances in Li 2 SO 4 and KOH electrolytes. The Co 3 O 4 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 Co 3 O 4 materials.