Inherent\nWater Competition Effect-Enabled Colloidal\nElectrode for Ultra-stable Aqueous Zn–I Batteries

Electrode\nmaterial stability is crucial for the development of\nnext-generation ultralong-lifetime batteries. However, current solid-\nand liquid-state electrode materials face challenges such as rigid\natomic structure collapse and uncontrolled species migration, respectively,\nwhich contradict the theoretical requirements for ultralong operation\nlifetimes. Herein, we present a design concept for a soft colloid\npolyvinylpyrrolidone iodine (PVP-I) electrode, leveraging the inherent\nwater molecule competition effect between (SO<sub>4</sub>)<sup>2–</sup> from the electrolyte and PVP-I from the cathode in an aqueous Zn||PVP-I\nbattery. Electrochemical demonstrations measured under various simulated\nand practical (integrated with photovoltaic solar panel) conditions\nhighlight the potential for an ultralong battery lifetime. The PVP-I\ncolloid exhibits a dynamic response to the electric field during battery\noperation. More importantly, the water competition effect between\n(SO<sub>4</sub>)<sup>2–</sup> from the electrolyte and water-soluble\npolymer cathode materials establishes a new electrolyte/cathode interfacial\ndesign platform for advancing ultralong-lifetime aqueous batteries.