Cu2+ intercalation boosts zinc energy reactivity of MnO2 with enhanced capacity and longevity

Rechargeable aqueous Zn-MnO2 batteries hold grand prospect in stationary energy storage, but the poor electronic conductivity and structural fragility of MnO2 cathode remain a troublesome issue. Herein, a layer-structured MnO2 with Cu2+ intercalation is demonstrated to show a boosted zinc energy reactivity and longevity. Theoretical calculations reveal that Cu2+ intercalation is of great assistance in increasing the electron conductivity of MnO2, reducing the migration barrier of Zn2+ carriers, and thus expediting the reaction kinetics. The implantation of Cu2+ ions could also endow the host structure with enriched active sites and enhanced cycling reversibility. Consequently, the Cu2+-intercalated MnO2 cathode exhibits remarkable zinc energy storage properties, including an improved capacity of 402.3 mAh g−1 at 0.2 A g−1, superb rate behavior, and prolonged lifespan (89.3% retention after 1000-cycling test at 2.0 A g−1). This study paves a foundation for an in-depth understanding of cation intercalation to advance MnO2 materials toward high-performance Zn batteries.