An Ultrafast and Ultra-Low-Temperature Hydrogen Gas–Proton Battery

Aqueous proton batteries are regarded as one of the most promising energy technologies for next-generation grid storage due to the distinctive merits of H+ charge carriers with small ionic radius and light weight. Various materials have been explored for aqueous proton batteries; however, their full batteries show undesirable electrochemical performance with limited rate capability and cycling stability. Here we introduce a novel aqueous proton full battery that shows remarkable rate capability, cycling stability, and ultralow temperature performance, which is driven by a hydrogen gas anode and a Prussian blue analogue cathode in a concentrated phosphoric acid electrolyte. Its operation involves hydrogen evolution/oxidation redox reactions on the anode and H+ insertion/extraction reactions on the cathode, in parallel with the ideal transfer of only H+ between these two electrodes. The fabricated aqueous hydrogen gas–proton battery exhibits an unprecedented charge/discharge capability of up to 960 C with a superior power density of 36.5 kW kg–1, along with an ultralong cycle life of over 0.35 million cycles. Furthermore, this hydrogen gas–proton battery is able to work well at an ultralow temperature of −80 °C with 54% of its room-temperature capacity and under −60 °C with a stable cycle life of 1150 cycles. This work provides new opportunities to construct aqueous proton batteries with high performance in extreme conditions for large-scale energy storage.