Hierarchically nanostructured ZnCo2O4 particles in 3D graphene networks for high-rate and long-life lithium ion batteries

Hierarchical ZnCo2O4 particles hosted by 3D graphene network were synthesized through a one-pot hydrothermal synthesis approach. The as-synthesized ZnCo2O4-graphene composites showed an outstanding overall electrochemical performance as an anode of lithium ion batteries with high specific capacity and excellent cycling stability, i.e., a reversible capacity of 1920 mAh g−1 at a current density of 1000 mA g−1 after 300 cycles. In particular, at an elevated current density of 4000 mA g−1, a high capacity of 1100 mAh g−1 could still be achieved, and it dropped by only 34% to 730 mAh g−1 after 2000 cycles. The synergistic roles of the hierarchically nanostructured ZnCo2O4 and highly-conductive 3D graphene networks in improving the specific capacity, rate performance, and cycling stability were discussed.