Tailoring MnO2 Cathode Interface via Organic–Inorganic Hybridization Engineering for Ultra-Stable Aqueous Zinc-Ion Batteries

Manganese (Mn)-based aqueous zinc ion batteries show great promise for large-scale energy storage due to their high capacity, environmental friendliness, and low cost. However, they suffer from the severe capacity decay associated with the dissolution of Mn from the cathode/electrolyte interface. In this study, theoretical modeling inspires that the amino acid molecule, isoleucine (Ile), can be an ideal surface coating material for α-MnO₂ to stabilize the surface Mn lattice and mitigate Mn dissolution, thereby enhancing cycling stability. Furthermore, the coated Ile molecular layers can accumulate Zn²⁺ ions from the electrolyte and promote those ions’ transport to the α-MnO₂ cathode while prohibiting H₂O from accessing the α-MnO₂ surface, reducing the surface erosion. The compact organic–inorganic interface is experimentally synthesized for α-MnO₂ utilizing Ile that shows homogeneous distribution on the well-defined Ile-α-MnO₂ nanorod electrodes. The fabricated aqueous zinc-ion battery exhibits a high specific capacity (332.8 mAh g⁻¹ at 0.1 A g⁻¹) and excellent cycling stability (85% after 2000 cycles at 1 A g⁻¹) as well as good inhibition toward Mn²⁺ dissolution, surpassing most reported cathode materials. This organic–inorganic hybrid interface design provides a new, simple avenue for developing high-performance and low-cost Mn-based aqueous zinc ion batteries (AZIBs).