Preparation of yolk–double shell Mn0.5Zn0.5Co2O4/C nanomaterials as anodes for high–performance lithium–ion batteries

Abstract

Ternary metal oxides have enormous potential in lithium–ion batteries (LiBs) owing to their tunable chemical composition and abundant active sites. In this work, we prepared Mn0.5Zn0.5Co2O4/C nanospheres with a yolk–double shell structure use doping Mn into ZnCo2O4 through a self-templating solvothermal method. The Mn0.5Zn0.5Co2O4/C nanospheres with yolk–double shell structure has a shell–layer thickness of about 34 nm, a carbon layer of 15 nm, and an inner–core diameter of approximately 78 nm. The peculiar yolk–double shell structure effectively can buffer the volume expansion and decrease the diffusion path of Li+, which improves the electrochemical performance. After 100 cycles at a current density of 200 mA g–1, the Mn0.5Zn0.5Co2O4/C nanospheres retained a specific capacity reaching 1001 mA h g–1. Even after 150 cycles at a higher current of 500 mA g–1, the specific capacity remained at 971 mA h g–1. Therefore, as an anode material for LiBs, the Mn0.5Zn0.5Co2O4/C nanospheres show high reversible capacity, superior cycling stability, and excellent electrochemical performance. Compared with ZnCo2O4, in Mn-doped ZnCo2O4, Mn can occupy the octahedral interstices of the spinel structure, which contributes to enhance the pseudocapacitive properties of the anode material, accelerate ion diffusion and improve charge transfer.