Single-phase ZnCo2O4 derived ZnO–CoO mesoporous microspheres encapsulated by nitrogen-doped carbon shell as anode for high-performance lithium-ion batteries

Abstract

The nanostructured hybrids composed of binary transition metal oxides (bi-TMOs) have emerged as promising anode materials in lithium ion batteries (LIBs) because of their unique physicochemical properties. Herein, we report ZnO/CoO mesoporous microspheres encapsulated by nitrogen-doped carbon shells (ZnO–CoO@NC) via self-templated solvothermal synthesis and subsequent in-situ pyrolysis of polypyrrole. The core of nanohybrid is derived from single-phase ZnCo2O4 microspheres and consists of uniform two-phase ZnO/CoO nanocrystals with interparticle mesopores. By virtue of the conductive layer of N-doped carbon and the interaction between mixed ZnO and CoO, the ZnO–CoO@NC mesoporous microspheres manifest the superior lithium storage properties as anode for LIBs, which exhibits the high Li+ storage capacity and the excellent cycling performance (1457 mAh g−1 at 0.5 A g−1 after 500 cycles), along with the competitive rate capability (381 mAh g−1 at 5 A g−1).