A Vanadium-doped CuxO Nanorod Array with Modulated Electronic Structure for Enhanced Aqueous Energy Storage

The poor intrinsic electronic conductivity of copper-based oxide materials limits their development for aqueous electrochemical energy storage devices (AEESDs). Herein, we developed a self-supporting vanadium-doped CuxO nanorod array AEESD via in situ transformation using a template precursor and modification with vanadium. Theoretical and experimental analyses illustrate that partial vanadium isomorphic substitution at copper sites can successfully modulate the electronic and lattice structure of the pristine materials, thereby driving electron transfer and resulting in enhanced electrical conductivity and reaction kinetics for energy storage. An AEESD constructed with a V-CuxO nanorod array negative electrode shows desirable electrochemical performance, with a high energy density of 1.26 mWh cm−2 at a power density of 8.50 mW cm−2 and 0.71 mWh cm−2 at 85 mW cm−2. The AEESD can effectively power LED lighting. This work provides novel insights into how modulation of the crystal structure of copper-based oxides can enhance their electrochemical performance.