Photo-rechargeable zinc-ion battery using highly ordered and vertically oriented C@VO2/ZnO microrod arrays

Abstract

Development of photo-rechargeable batteries is a potential resolution for supplying off-grid solar power system in remote locations. Here, we present a photo-rechargeable zinc-ion battery (PRZIB) that can be directly recharged by the light without external photovoltaic cells and controllers. A highly ordered and vertically oriented ZnO microrod arrays (ZMRAs) are prepared using hydrothermal method in micron-scale patterned substrate defined by lithographic technology, which are used to incorporate with carbon coated vanadium oxide (C@VO2) nanocomposite to form a large specific surface area of three-dimensional network of C@VO2/ZnO heterojunction. PRZIB is assembled using C@VO2/ZMRAs structure as the photo-cathodes as well as intercalation host for Zinc-ions, which demonstrates a photo-conversion efficiency of 3.3% and gravimetric capacities of 286.0 mAh g−1 and 339.3 mAh g−1 at 500 mA g−1 in dark and light conditions. An excellent long-term cycling stability is achieved with a capacity retention of 88.79% after 300 cycles at 1000 mA g−1 in dark condition. It is suggested that the distinctive morphologies and structure of C@VO2/ZMRAs provide effective strategies for enhancing photo-electrochemical redox reaction kinetics.