Synthesis of ZnO-Cu-C yolk-shell hybrid microspheres with enhanced electrochemical properties for lithium ion battery anodes

Abstract

Zinc-copper citrate porous, yolk-shell and hollow microspheres are controllably produced via a facile electrostatic interplay between zinc citrate solid microspheres and copper sulphate solution with controllable concentration. By calcination of the firstly acquired zinc-copper citrate precursors in inert atmosphere, the corresponding ZnO-Cu-C porous, yolk-shell and hollow hybrid microspheres are synthesized. When adopted as the electrode materials for lithium ion batteries, the produced ZnO-Cu-C yolk-shell hybrid microspheres depict higher reversible capacity and better cycling stability than ZnO-Cu-C porous hybrid microspheres. After 500 cycles at 200mAg−1, yolk-shell hybrids deliver a reversible capacity of 769mAhg−1. Additionally, ZnO-Cu-C hollow hybrid microspheres exhibit best rate capability, which is due to their special three dimensional Cu conductive network.