Tunable Organic-Inorganic p-π-d Electron Conjugation Triggers d-π Hybridization in Quinonized MnO₂ Superlattice toward Ultrastable and High-Rate Zn−MnO₂ Batteries

Zn-MnO₂ batteries with two-electron transfer harvest high energy density, high working voltage, inherent safety, and cost-effectiveness. Zn²⁺ as the dominant charge carriers suffer from sluggish kinetics due to the strong Zn²⁺−MnO₂ coulombic interaction, which is also the origin of pestilent MnO₂ lattice deformation and performance degradation. Current studies particularly involve H⁺ insertion-dominating chemistry, where the long-term cycle stability remains challenging due to the accumulative Zn²⁺ insertion and structural collapse. Herein, a simultaneously enhanced and stabilized Zn²⁺/H⁺ co-insertion chemistry is proposed by the quinone-hybridized MnO₂ superlattice, a first-of-this-kind structure with a distinctive organic–inorganic-extended p-π-d conjugation, which enables a tunable interlayer d-π hybridization. Theoretical and experimental results substantiate that the interlayer d-π hybridization triggers the enhancement of polarons occupancy near Fermi level, the downward shift of O p-band center, the elevated Mn t_2g occupation and thus improved [MnO₆] stability upon unprecedentedly high Zn²⁺ contribution. The notable d-π hybridization endows MnO₂ superlattice an ultrahigh specific capacity (435.9 mAh g⁻¹ at 0.25 A g⁻¹), state-of-the-art cycle stability (~100 % capacity retention after 30,000 cycles at 10 A g⁻¹) with substantially enhanced rate performance. Our findings enlighten a new paradigm in the adjustment of Zn²⁺/H⁺ co-insertion chemistry towards high-performance rechargeable aqueous batteries.