Graphdiyne Oxide‐Enabled Solid‐State Proton Battery Exhibiting Superior Rate Capability

ABSTRACT Proton batteries are emerging as a promising next‐generation energy storage technology, featuring high safety, superior power density, and excellent stability. However, the development of solid‐state electrolytes with high proton conductivity remains a significant challenge. Herein, graphdiyne oxide (GDYO) is proposed as a novel solid‐state electrolyte for proton batteries for the first time. By constructing a three‐dimensional hydrogen bonding network with phosphoric acid, the resulting GDYO@H 3 PO 4 electrolyte effectively addresses the low conductivity issue of conventional solid‐state electrolytes at room temperature. Fourier‐transform infrared (FTIR) spectroscopy and solid‐state fluorescence spectroscopy confirm the formation of an interconnected hydrogen bonding network between GDYO sheets and H 3 PO 4 , facilitating efficient proton transport via a hopping transport mechanism. The assembled hydrous vanadium hexacyanoferrate//MoO 3 (VHCF//MoO 3 ) full solid‐state proton battery demonstrates superior rate capability, retaining 53.6% of its capacity retention at an ultrahigh charge–discharge rate of 50C. Furthermore, the battery delivers remarkable cycling stability with a specific capacity of 102.2 mAh g − 1 and 90.2% capacity retention after 4500 cycles, significantly outperforming state‐of‐the‐art systems. This research will provide a new way to construct solid‐state proton battery with long cycling stability and high performance, and highlight the exceptional potential of GDYO as a molecular‐level design platform for advanced electrocatalysts in solid‐state batteries.