Oxygen-site engineering guided bonding coupling and intrinsic distortion: Enabling high-rate long-lasting Zn-MnO2 batteries

Abstract

Manganese oxides are widely recognized as promising cathodes for grid-scale aqueous zinc-ion batteries (AZIBs) owing to their cost benefit and excellent capacity, but the notorious Jahn-Teller effect and sluggish diffusion kinetics, especially at high current-density, inducing severe structural collapse, poor cycleability and limited rate during repeated switching between active Mn³⁺ and non-active Mn⁴⁺. Herein, we introduce intrinsic distortion and new bonding structure (P-O-Mn bridging linkages and Mn-S bonds) into δ-MnO₂ via oxygen-site engineering based on P and S heteroatom collaborative modification for constructing MnO₂ cathode with high reactivity, rich defects and low-valence Mn. The intrinsic distortion in MnO₂ matrix and electrochemical heterointerface caused by bonding structure coupling suppress J-T distortion and interface side reactions during cycling, enhancing recyclability and structural stability. Furthermore, tailored MnO₂ cathode selectively accelerates Zn²⁺ (Mn-S bond as main function) and H⁺ (bridging linkage as main function) transport kinetics while enhancing electron transport capability, leading to better rate performance. As a result, tailored Zn-MnO₂ cell delivers high-rate endurance (192.5 mAh g^-1 at 10 A g^-1) and long-lasting stability (96% capacity retention over 4500 cycles at 10 A g^-1). Our work highlights the significant promise of distortion engineering and bonding chemistry for optimizing cathode in practical Zn batteries.