Urea-assisted solvothermal synthesis of monodisperse multiporous hierarchical micro/nanostructured ZnCo2O4 microspheres and their lithium storage properties

High-quality monodisperse multiporous hierarchical micro/nanostructured ZnCo2O4 microspheres have been fabricated by calcinating the Zn1/3Co2/3CO3 precursor prepared by urea-assisted solvothermal method. The as-prepared products are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and Brunauer-Emmett-Teller (BET) measurement to study the crystal phase and morphology. When tested as anode material for lithium ion batteries, the multiporous ZnCo2O4 microspheres exhibit an initial discharge capacity of 1,369 mAh g−1 (3,244.5 F cm−3) and retain stable capacity of 800 mAh g−1 (1,896 F cm−3) after 30 cycles. It should be noted that the good electrochemical performances can be attributed to the porous structure composed of interconnected nanoscale particles, which can promote electrolyte diffusion and reduce volume change during discharge/charge processes. More importantly, this ZnCo2O4 3D hierarchical structures provide a large number of active surface position for Li+ diffusion, which may contribute to the improved electrochemical performance towards lithium storage.