Constructing an Al2O3/(NH4)2V4O9 heterostructure as a cathode material for high performance aqueous rechargeable zinc ion batteries

Abstract

An Al₂O₃/(NH₄)₂V₄O₉ heterostructure is fabricated as a cathode material for aqueous rechargeable zinc ion batteries. This is the first report that Al₂O₃ assists (NH₄)₂V₄O₉ to improve the electrochemical performance of zinc-ion batteries. The Al₂O₃ content in the Al₂O₃/(NH₄)₂V₄O₉ heterostructure can be controlled by adjusting the ratio of Al : V, and the Al₂O₃/(NH₄)₂V₄O₉ nanoblocks with an Al₂O₃ content of 15.98% deliver excellent electrochemical performance with a maximum discharge capacity of 269 mAh g⁻¹ at a current density of 0.5 A g⁻¹. At a high current density of 5.0 A g⁻¹, the Al₂O₃/(NH₄)₂V₄O₉ cathode displays an activated maximum capacity of 200 mA h g⁻¹, and the specific capacity can be maintained at 173 mAh g⁻¹ with a maximum capacity retention of 86.5% after 3000 cycles. The excellent electrochemical performance mainly come from the internal electronic field at the heterointerfaces in the Al₂O₃/(NH₄)₂V₄O₉ heterostructure.