Soft Colloidal Electrode Enabled by Water Distribution Control for Ultra-Stable Aqueous Zn-I Batteries.

Abstract

Designing effective electrode material is crucial for developing ultra-long lifetime batteries, thereby reducing daily battery costs. Current electrode materials are typically solid or liquid state, with an intermediate colloidal state offering the advantages of fixed redox-active species, akin to solid-state materials, and the absence of rigid atomic structure, akin to liquid-state materials, while avoiding the particle pulverization and uncontrolled migration. Herein, an aqueous Zn||Pluronic F127 (PF127)/ZnI₂ colloid battery is developed utilizing the inherent water molecular control effect of ZnSO₄. In this system, ZnSO₄ in the electrolyte acts as a water molecular valve, regulating the water content within the PF127 polymer to form a PF127 colloid. The resulting aqueous Zn||PF127/ZnI₂ colloid battery exhibits an ultra-long cycling lifetime and compatibility with various simulated and practical operating conditions, highlighting its potential for practical applications. Additionally, this battery design concept offers a platform for constructing ultra-stable aqueous batteries.