Hard‐Soft Acid‐Base Guided Interfacial Reinforcement of Inorganic Organic Hybrid Cathodes for High Performance Aqueous Zinc Ion Batteries

ABSTRACT The interfacial incompatibility between inorganic metal oxides and polymers severely limits the utilization of hybrid cathodes in aqueous zinc‐ion batteries (AZIBs). Herein, we propose a Cu 2+ ion mediated interfacial reinforcement strategy guided by the hard‐soft acid‐base principle to strengthen the interaction between α‐MoO 3 and polyaniline (PANI). The introduced borderline acidic Cu 2+ ions on the α‐MoO 3 surface provides effective anchoring sites for PANI through strong Cu‐N coordination, which accelerates the in‐situ growth of PANI, suppresses polymer self‐aggregation, thus enabling a uniform coating on MoO 3 nanorods. In addition, Cu 2+ incorporation selectively promotes the exposure of MoO 3 facets that are thermodynamically favorable for PANI adsorption, further enhancing interfacial compatibility. As such, the PANI loading is increased by 66.79%, forming a conformal shell structure on MoO 3 . The hybrid cathode exhibits suppressed proton penetration, mitigated parasitic reactions, accelerated zinc ion transport kinetics, and robust structural integrity. Consequently, the cathode delivers a high specific capacity of 397.20 mAh g − 1 at 0.2 A g − 1 and maintains 278.35 mAh g − 1 even at 10 A g − 1 . After 5000 cycles at 5.0 A g − 1 , it retains 98.95% of its initial capacity with Coulombic efficiency approaching unity (∼100%) in AZIBs. This work provides a general interfacial engineering strategy for constructing high performance hybrid electrodes.