Unique porous yolk-shell structured Co3O4 anode for high performance lithium ion batteries

This paper introduces a unique porous yolk-shell structured Co3O4 microball, which is synthesized by spray pyrolysis from precursor solution with polyvinylpyrrolidone (PVP) additive. PVP acts as an organic template in the pyrolytic reaction facilitating the formation of yolk-shell structure. The electrochemical properties of porous yolk-shell Co3O4 microballs evaluated as anode materials for lithium ion batteries exhibit high initial columbic efficiency of 77.9% and high reversible capacity of 1025 mAh g−1 with capacity retention of 98.8% after 150 cycles at 1 A g−1. In contrast, the hollow microballs obtained without PVP addition show obvious capacity decay from 1033 to 748 mAh g−1 after 150 cycles with the capacity retention of 72.3%. In addition, the microballs with porous yolk-shell structure exhibit better rate performance. The superior electrochemical performance is mainly attributed to the unique porous yolk-shell structure which provides large voids to buffer volume expansion and enlarge the contact area with the electrolyte, shortening the diffusion path of the lithium ions.