An Aqueous Dual‐Ion Battery Cathode of Mn₃O₄ via Reversible Insertion of Nitrate

Abstract

We report reversible electrochemical insertion of NO₃ ^- into manganese(II, III) oxide (Mn₃ O₄ ) as a cathode for aqueous dual-ion batteries. Characterization by TGA, FTIR, EDX, XANES, EXAFS, and EQCM collectively provides unequivocal evidence that reversible oxidative NO₃ ^- insertion takes place inside Mn₃ O₄ . Ex situ HRTEM and corresponding EDX mapping results suggest that NO₃ ^- insertion de-crystallizes the structure of Mn₃ O₄ . Kinetic studies reveal fast migration of NO₃ ^- in the Mn₃ O₄ structure. This finding may open a new direction for novel low-cost aqueous dual-ion batteries.