Co3O4 nanosheets anchored on C/Cu porous microspheres as high-performance anode materials for lithium-ion battery

As electrode materials, transition metal oxides (TMOs) exhibit poor electrochemical performances owing to their inherent low electronic conductivity and considerable volume expansion and contraction during charge/discharge cycles. Designing TMOs with unique nanostructure and combining them with conductive carbon substrates are effective strategies to address the inherent issues. In this work, we designed C/Cu porous microspheres and grew Co3O4 nanosheets (NS) vertically on the carbon walls using an in situ synthesis route. As a conductive substrate, the C/Cu microspheres provide a hierarchical pore network and an electrode/electrolyte contact interface with large area, which can substantially enhance electron and ion diffusion kinetics. The in situ synthesized Co3O4 NSs are firmly anchored on the carbon walls, thereby increasing the structural durability of the composites in long-term cycling. Due to their unique structural characteristics, when using the C/Cu@Co3O4 composite microspheres as the anode materials for lithium-ion batteries, the batteries exhibit an enhanced rate performance (a high reversible specific capacity of 622 mA h g−1 at a current density of 5000 mA g−1), high charge-specific capacity (907 mA h g−1 at 100 mA g−1 after 200 cycles, and a stable specific capacity of 944 mA h g−1 over 800 cycles, even at a high current density of 1000 mA g−1), and excellent cycling stability.