Ultralow-Temperature Aqueous Conductive Polymer–Hydrogen Gas Battery

Hydrogen gas batteries are regarded as one of the most promising rechargeable battery systems for large-scale energy storage applications due to their advantages of high rates and long-term cycle lives. However, the development of cost-effective and low-temperature-tolerant hydrogen gas batteries is highly desirable yet very challenging. Herein, we report a novel conductive polymer–hydrogen gas battery that is suitable for ultralow-temperature energy storage applications and consists of a hydrogen gas anode, a conductive polymer cathode using polyaniline (PANI) or polypyrrole as examples, and protonic acidic electrolytes. The PANI–H2 battery using 1 M H2SO4 as the electrolyte exhibits a capacity of 67 mA h/g, a remarkable rate up to 15 A/g, a Coulombic efficiency around 100%, and an ultra-long life of 10,000 cycles. Using the anti-freezing 9 M H3PO4 electrolyte, the PANI–H2 battery can operate well at temperatures down to −70 °C, which maintains ∼70% of the capacity at room temperature and shows an excellent cycle stability under −60 °C. Benefiting from the fast redox kinetics of both electrodes, this work demonstrates excellent rate performance and low-temperature feasibility of conductive polymer-H2 batteries, providing a new avenue for further development of low-cost and reliable polymer-H2 batteries for large-scale energy storage.