Facile synthesis of uniform mesoporous ZnCo2O4 microspheres as a high-performance anode material for Li-ion batteries

In this paper, three dimensional (3D) uniform ZnCo-glycolate precursor microspheres composed of nanosheets were successfully synthesized via a facile ethylene glycol (EG) mediated solvothermal method. Through moderate calcination of the as-synthesized ZnCo-glycolate precursor, they could be converted into uniform mesoporous ZnCo2O4 microspheres with surrounding nanoparticles. The obtained samples were systematically characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and N-2 adsorption-desorption. The results demonstrated that tuning of the surface texture and the pore size of the ZnCo2O4 products were very significant in Li-ion batteries (LIBs). The uniform mesoporous ZnCo2O4 microspheres exhibit excellent high specific capacity, superior rate capability, and enhanced cycling performance. At a current density of 100 mA g(-1), the uniform mesoporous ZnCo2O4 microspheres exhibited excellent initial specific capacity of 1332 mAh g(-1). The capacity maintain at 721 mAh g(-1) after 80 discharge-charge cycles. Even as current density reached to 1000 mA g(-1), the initial specific capacity still showed 937 mAh g(-1) and the discharge capacity of 432 mAh g(-1) was retained after 40 cycles.