Wrapping Porous Hierarchical Co₃O₄ Nanospheres within Reduced Graphene Oxide Nanosheets for High-Performance Lithium Storage

Transition metal oxide-based anode materials possess high theoretical capacity and abundant resources but are limited by severe volume variation and intrinsic low conductivity, thus leading to rapid capacity decay and poor rate performance. Herein, we develop a strategy to prepare porous hierarchical Co₃O₄ nanopsheres by controlling the annealing process of Co-gluconates, and the Co₃O₄ nanospheres were successfully wrapped by rGO nanosheets with good dispersion through facile hydrothermal treatment. The Co₃O₄/rGO electrode demonstrates outstanding lithium storage properties, delivering a reversible capacity of 949.4 mA h g^-1 at 500 mA g^-1 after 300 cycles and 512.3 mA h g^-1 at 2000 mA g^-1 even after 1000 cycles. The introduction of rGO nanosheets not only greatly enhances the electron conductivity but also offers high pseudocapacitive lithium storage behavior. More importantly, the integration of porous hierarchical electrode materials with conductive matrices can be generally applied for the development of high-performance energy storage devices.