CuO nanosheets embedded on carbon microspheres as high-performance anode material in lithium-ion batteries

Because of its high capacity, availability, and environmental friendliness, copper oxide (CuO) is a desirable anode material for lithium-ion batteries (LIBs). However, due to low intrinsic electrical conductivity and enormous volume expansion during cycling, the capacity utilization and cycle stability of the CuO anode remain insufficient for battery applications. In this study, we design and fabricate a three-dimensional (3D) porous carbon@CuO composite (C@CuO) by in situ synthesis of CuO nanosheets directly on the internal and external walls of chitin-derived carbon microspheres. Benefiting from the hierarchical conductive framework of the carbon microspheres and a rational distribution of CuO nanosheets, the capacity utilization and structural stability of the CuO nanosheets are substantially improved during the charge/discharge process. Thus, the C@CuO microspheres as the anode material for LIBs demonstrate a high reversible capacity of 626 mA h g−1 at 100 mA g−1 with a capacity retention of ∼93% over 200 cycles, a stable specific capacity of 553 mA h g−1 after 600 cycles even at a high current density of 1000 mA g−1, and superior rate capability with a high discharge capacity of 262 mA hg−1 at 5000 mA g−1. Therefore, this study innovatively constructs carbon microspheres with a hierarchical structure accompanied by self-growing CuO nanosheets as the anode material for LIBs, which may provide a new idea for the rational design of 3D carbon/metal oxide hybrids.