Turning crisis into opportunity: Intrinsically polarised low concentration eutectic electrolytes enable highly reversible zinc anodes

Abstract

Low-concentration electrolytes (LCEs) hold great promise for sustainable energy storage due to their low viscosity, excellent wettability, and cost-effectiveness. However, their intrinsic polarization issues often lead to side reactions and dendrite growth, hindering their broader application. Herein, we present an approach to convert the negative effects of intrinsic polarization in LCEs into advantages, overcoming these challenges. The experimental and theoretical analyses demonstrate that acetate-adsorbed zinc anodes can harness the intrinsic polarization of LCEs to direct the electrocrystallization process on their surfaces. This promotes the preferential orientation of Zn(002) plane with high stability, resulting in symmetric batteries loaded with low-concentration eutectic electrolytes (LCEE) that maintain surprisingly low voltage polarization during the dendrite-free growth of up to 3150 h. In addition, by forming an organic-inorganic composite film enriched with N and Cl, LCEE achieves rapid migration of Zn²⁺. This allows Zn//PANI full batteries with LCEE to demonstrate superior capacity and cycling stability compared to other Zn-based batteries with LCEs. This study not only achieves a divergent design in LCEs but also provides clear guidance for future electrolyte development.