Facile synthesis of porous ZnCo2O4 micro–flower decorated with SWCNTs toward superior lithium storage performance

Abstract

Binary metal oxides ZnM2O4 (A = Co, Fe, Mn) with spinel structures have been widely studied for their high theoretical specific capacity, relatively low cost, controllable morphology and synergistic effect between metal oxides with different charging and discharging mechanisms. However, the electrochemical properties are seriously affected by the huge volume change during cycles and poor electronic conductivity. In this work, porous ZnCo2O4 micro–flowers self–assembled from nano–sheets are successfully prepared by a simple solvothermal method followed by a heat treatment process without the aid of any soft/hard templates, and the resulting ZnCo2O4 active material is further decorated with SWCNTs. The phase composition, morphology characteristic, specific surface area, pore size distribution, elemental valence state and other information of the as–prepared samples are analyzed by relevant techniques such as XRD, FTIR, FESEM, (HR)TEM, TGA, Raman, N2 adsorption/desorption measurement and XPS. As anode materials in Li–ion batteries, the ZnCo2O4/SWCNTs product exhibits high charge/discharge specific capacity, excellent cycling stability and remarkable rate capability. Excellent electrochemical performance benefits from the special micro–/nano–structure characteristics of the as–synthesized ZnCo2O4/SWCNTs electrode material and good dynamic characteristics during cycling.