Enhanced electrochemical properties of graphene-wrapped ZnMn2O4 nanorods for lithium-ion batteries

Abstract

Thermally reduced graphene oxide (rGO)-wrapped ZnMn₂O₄ nanorods have been successfully fabricated via a facile bottom-up approach. Characterization results show that porous ZnMn₂O₄ nanorods are uniformly wrapped by ultrathin rGO sheets. The unique structure of this rGO–ZnMn₂O₄ composite could facilitate both ion and electron diffusion, thus providing suitable characteristics of an anode material for high performance lithium-ion batteries. Specifically, the conductive rGO sheets could act as an efficient buffer to relax the volume changes from Li⁺ insertion/extraction, and enable the structural and interfacial stabilization of ZnMn₂O₄ crystals. As a consequence, a high and stable reversible capacity (707 mA h g⁻¹ at 100 mA g⁻¹ over 50 cycles) and an excellent rate capability (440 mA h g⁻¹ at 2000 mA g⁻¹) are achieved with this composite material.