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

Abstract

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 N₂ 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.