Rechargeable Hydrogen-Chlorine Battery Operates in a Wide Temperature Range

Hydrogen-chlorine (H-2-Cl-2) fuel cells have distinct merits due to fast electrochemical kinetics but are afflicted by high cost, low efficiency, and poor reversibility. The development of a rechargeable H-2-Cl-2 battery is highly desirable yet challenging. Here, we report a rechargeable H-2-Cl-2 battery operating statically in a wide temperature ranging from -70 to 40 degrees C, which is enabled by a reversible Cl-2/Cl- redox cathode and an electrocatalytic H-2 anode. A hierarchically porous carbon cathode is designed to achieve effective Cl-2 gas confinement and activate the discharge plateau of Cl-2/Cl- redox at room temperature, with a discharge plateau at similar to 1.15 V and steady cycling for over 500 cycles without capacity decay. Furthermore, the battery operation at an ultralow temperature is successfully achieved in a phosphoric acid-based antifreezing electrolyte, with a reversible discharge capacity of 282 mAh g(-1) provided by the highly porous carbon at -70 degrees C and an average Coulombic efficiency of 91% for more than 300 cycles at -40 degrees C. This work offers a new strategy to enhance the reversibility of aqueous chlorine batteries for energy storage applications in a wide temperature range.