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.