Achieving Stable Copper Ion Storage in Layered Vanadium Pentoxide

Copper metal is a promising anode in aqueous batteries due to its low price, noble reaction potential (0.34 V), high theoretical specific capacity, abundance and chemical stability. However, only a few copper ion storage materials have been reported. Herein, layered vanadium pentoxide is chosen to store copper ions for the first time. Ex situ XRD reveals a unique two phase transition process during cycling. The V2O5 electrode shows stable copper ion storage performance. It delivers 91.9 mAh g−1 for the first cycle with a cycle life of as high as 4000 cycles at 1.0 A g−1. This work provides an intriguing copper ion storage material and expands the available options of electrode materials for copper ion storage.