Construction of vanadium oxide cathode material with high performance and stability and its application in aqueous zinc-ion battery

Abstract

The vanadium oxide cathode material is widely regarded as a promising candidate for aqueous zinc-ion batteries (AZIBs). However, its low activity, poor cycling stability, and inadequate rate performance have significantly impeded its commercial viability. In this study, we report a composite electrode material of V2O5 modified with La3+ and phytic acid (LPVO) with enhanced electrochemical performance. The La3+ are capable of intercalating into the interlayer of V2O5, effectively expanding the interlayer spacing for fast Zn2+ transport, and facilitating the exposure of more Zn2+ storage sites with improved capacity. Additionally, the encapsulated phytic acid could serve as a protective layer to prevent the detachment and dissolution of vanadium compounds during cycles, thereby improving the electrochemical stability. Under the current density of 0.1 A g−1, the capacity of LPVO electrode reaches as high as 385 mAh g−1. Even after 2000 charge–discharge cycles, the capacity retention rate remains as high as 75% (at 3 A g−1). Compared to commercial V2O5, the Zn2+ diffusion rate of the LPVO composite is improved by nearly 1000 times, reaching 5∼7 × 10−10 cm2 s−1. This approach is universally applicable to enhance electrochemical performance of diverse layered electrode materials, aiding the rapid advancement of cathode design for AZIBs.