Inherent Water Competition Effect-Enabled Colloidal Electrode for Ultra-stable Aqueous Zn–I Batteries
Kaiqiang Zhang, Chao Wu, Shiye Yan, Changlong Ma, Luoya Wang, Pei Kong, Kun Zhuang, Pengcheng Fan, Jilei Ye, Yuping Wu
Abstract
Electrode material stability is crucial for the development of next-generation ultralong-lifetime batteries. However, current solid- and liquid-state electrode materials face challenges such as rigid atomic structure collapse and uncontrolled species migration, respectively, which contradict the theoretical requirements for ultralong operation lifetimes. Herein, we present a design concept for a soft colloid polyvinylpyrrolidone iodine (PVP-I) electrode, leveraging the inherent water molecule competition effect between (SO 4 ) 2– from the electrolyte and PVP-I from the cathode in an aqueous Zn||PVP-I battery. Electrochemical demonstrations measured under various simulated and practical (integrated with photovoltaic solar panel) conditions highlight the potential for an ultralong battery lifetime. The PVP-I colloid exhibits a dynamic response to the electric field during battery operation. More importantly, the water competition effect between (SO 4 ) 2– from the electrolyte and water-soluble polymer cathode materials establishes a new electrolyte/cathode interfacial design platform for advancing ultralong-lifetime aqueous batteries.