Organic-inorganic hybrid cathode enabled by in-situ interface polymerization engineering boosts Zn²⁺ desolvation in aqueous zinc-ion batteries

Rechargeable aqueous zinc-ion batteries (RAZIBs) have attracted considerable attention for application in large-scale energy storage systems. However, the progress of RAZIBs has been hindered by the sluggish reaction kinetics and poor structural stability, which are closely associated with the desolvation process of hydrated Zn²⁺. To overcome these issues, an in situ interfacial polymerization strategy is proposed to uniformly germinate a polyaniline (PANI) layer on α-MnO₂ and form an organic-inorganic hybrid cathode (MnO₂@PANI). Theoretical calculations and experimental characterizations disclose that the polyaniline layer equipped with hydrophilic functional groups can effectively trap the active water molecules to break the strong attraction between H₂O and Zn²⁺, thereby facilitating the desolvation process of hydrated Zn²⁺, and regulating the Zn²⁺ diffusion kinetics and electrode reaction kinetics on the cathode/electrolyte surface. Meanwhile, the irreversible phase evolution and dissolution of active species are largely suppressed due to the PANI shell protecting the α-MnO₂ from the attack of active water molecules. As a consequence, the organic-inorganic hybrid cathode exhibits 401.9 mAh/g after 200 cycles at a current density of 0.5 A/g and long-term durability over 1000 cycles at a current density of 2.0 A/g without irreversible phase transformation. This work provides insight into the regulation of the desolvation process for high performance aqueous energy storage systems.