Rationally designed tungsten trioxide nanosheets for high-efficiency aqueous battery application

Aqueous battery (AB) with non-metallic charging carriers is a viable candidate for grid energy storage devices owing to its comparatively low cost and high safety. However, developing practical electrode materials with remarkable electrochemical performance remains a great challenge. In this study, tungsten trioxide nanosheets (WONSs) with one-dimensional tunnels were facilely synthesized through a hydrothermal reaction. When used as the cathode material in aqueous batteries, the as-prepared WONS exhibits excellent long-term cycling stability and impressively high rate capability due to the nearly zero-strain structural characteristics of super-fast proton storage. Notably, a stable cycling performance with 89% capacity retention after 10000 cycles was achieved with an increased mass loading of WONS at around 12 mg cm⁻². Our work points to a new direction of promoting high-efficiency AB applications with protons as charge carriers in a mild electrolyte.