Electrolyte Engineering for Low-Temperature Aqueous Batteries: Strategies, Mechanisms, and Perspectives

Abstract

Aqueous batteries offer inherent safety and environmental advantages, yet their deployment is critically constrained by severe performance degradation below 0°C, where capacity losses exceed 50-80% and complete failure occurs below -20°C. This limitation significantly restricts applications in rapidly expanding cold-climate sectors including Arctic operations and winter electric mobility. This comprehensive review presents a systematic analysis of electrolyte modification strategies through four primary approaches: concentration engineering, inorganic additives, organic additives, and gel electrolyte architectures. Unlike previous reviews focusing on individual techniques, this work establishes a holistic framework integrating molecular-level mechanisms with macroscopic performance outcomes. Recent advances demonstrate remarkable progress: concentration engineering enables operation to -70°C through higher concentration mechanisms, inorganic additives achieve stable cycling at -60°C via hydrogen bonding disruption, organic additives provide multi-functional enhancement to -55°C through coordinated solvation engineering, and gel electrolytes deliver robust performance at -50°C through synergistic polymer-additive interactions. Advanced characterization reveals optimal performance requires multi-scale synergistic regulation across molecular solvation environments, interfacial processes, and bulk transport properties. Critical gaps include incomplete understanding of interfacial evolution during thermal cycling and limited predictive capability for multi-component optimization. This analysis establishes fundamental design principles and identifies priority research directions for translating laboratory breakthroughs into commercially viable low-temperature aqueous battery technologies.