Facile synthesis of Co3O4 hierarchical microspheres with improved lithium storage performances

Abstract Porous nanosheets-assembled Co 3 O 4 microspheres have been first successfully fabricated by a facile solvothermal method without any surfactant followed by a relatively low annealing temperature (400 °C) with a higher specific surface area compared to the annealing temperature of 600 °C. The nanosheets-assembled microspheres exhibit a high discharge capacity of 1000 mA h g −1 at a current density of 100 mA g −1 after 50 cycles and 850 mA h g −1 at a current density of 500 mA g −1 after 80 cycles, even at a high current density of 1.6 A g −1 the cycling reversible capacity can still keep 750 mA h g −1 , the representative capacities are relatively higher than most of reports about pure Co 3 O 4 . We attribute the excellent electrochemical performances to the porous nanosheets structure and architectures, which can provide more effective electrode/electrolyte contact area and direct ion transmission path, then lead to faster lithium-ion diffusion, confirmed by EIS measurements. The high specific capacity, excellent cycling and rate performances demonstrate that the porous nanosheets assembled microspheres present promising application in lithium storage.