Regulating Fast Anionic Redox for High-Voltage Aqueous Hydrogen-Ion-based Energy Storage.

The ionic conductivity and small size of the hydrogen ion make it an ideal charge carrier for hydrogen-ion energy storage (HES); however, high-voltage two-electrode configurations are difficult to construct as the result of the lack of efficient cathodic energy storage. Herein, the high potential fast anionic redox at the cathode of reduced graphene oxide (rGO) was applied by introducing redox additive electrolytes. By coupling the storing hydrogen ion in the Ti3 C2 Tx at the anode, a HES with a voltage of 1.8 V and a plateau voltage at 1.2 V was constructed. Compared with 2.2 Wh kg-1 for the low-voltage Ti3 C2 Tx //Ti3 C2 Tx , the specific energy of asymmetric rGO//Ti3 C2 Tx reaches 34.4 Wh kg-1 . Furthermore, it possesses an energy density of 23.7 Wh kg-1 at high power density of 22.5 kW kg-1 . Thus, this study provides a novel guideline for constructing high-voltage fast HES full cells.