Carbonate-assisted hydrothermal synthesis of porous hierarchical Co3O4/CuO composites as high capacity anodes for lithium-ion batteries

Through thermal decomposition of hybrid carbonate (Cu, Co)2(OH)2CO3 precursors synthesized by a simple carbonate-assisted hydrothermal method, porous hierarchical Co3O4/CuO composites with different ratios of Co to Cu were successfully fabricated. A cooperative self-assembly effect of different carbonates has been proposed to explain the formation of nanosheets assembled hierarchical (Cu, Co)2(OH)2CO3 precursor. Electrochemical lithium storage properties of all the composites are evaluated as anode materials for lithium-ion batteries. It is found that the ratio of Co to Cu plays a vital role in affecting the morphology, structure and subsequent electrochemical performance of the Co3O4/CuO composites. Owing to the superior porous hierarchical structure and synergistic lithium storage effect of both active electrode materials, the Co3O4/CuO composites demonstrate higher capacities and enhanced cycling stability compared to pure Co3O4 or CuO electrodes. The Co3O4/CuO composite (Co: Cu = 6: 1) electrode delivers a high reversible capacity of 1056 mAh g−1 at a current density of 200 mA g−1 for 500 cycles. With the superior electrochemical performance and easy preparation, the porous hierarchical Co3O4/CuO composites demonstrate promising application potential as anode materials for next generation high performance LIBs.