Co3O4/nitrogen-doped graphene promise high-performance sodium-ion battery anode

Co3O4 has been diffusely researched for high theoretical capacities and superior security. However, its poor intrinsic conductivity and serious volume effects during Na-ion insertion/extraction restrict its actual applications. Herein, graphene oxide coated Co3O4 nanoparticle are integrated through a straightforward hydrothermal method and freeze-drying treatment followed by annealing process. The characterization results indicate that the Co3O4 nanoparticles (∼20 nm) were loaded onto N-GO (∼75 nm), and nitrogen element was successfully introduced through urea. The unique Co3O4/N-GO structure suffices competent stress relaxation and fast Na+ and electron transfer during discharge/charge cycles. Consequently, the Co3O4/N-GO electrode displays a high discharge capacity of 323 mA h g−1 at 0.1 A g−1. When coupled with Na3V2(PO4)3 (NVP) cathode), the NVP//Co3O4/N-GO battery exhibits significant energy density (249.9 Wh kg−1) and power density (163.3 W kg−1).