Comprehensive Understanding of Accelerated Kinetics Driven by Anion–Diluent Dynamics Enabling Wide Temp Operation in Dual-Ion Batteries

Pioneering advancements in energy storage necessitate electrolyte innovations that enhance ion transport and reduce resistance. While considerable progress has been achieved, existing research predominantly explores cationic solvation structures, leaving the behavior of anions insufficiently addressed. Here, elucidate the previously ambiguous role of anion–diluent interactions by correlating solvation structures with kinetic behavior, thereby unveiling their mechanistic contribution from the bulk electrolyte environment to electrochemical reaction processes. Unlike traditional lithium-ion-centered studies in localized high-concentration electrolytes (LHCEs), this study provides an anion-centric perspective on solvation dynamics and demonstrates its efficacy in dual-ion battery (DIB) systems, where both cations and anions participate in electrochemical redox processes. These transient anion–diluent interactions enhance anion mobility in the electrolyte, promote desolvation efficiency at interfaces, and reduce the reorganization energy. LHCE also prevents anion decomposition at high voltages, lowers interfacial resistance, and enhances structural stability by refining anion intercalation mechanisms in graphite. This study lays out a multiscale, comprehensive interpretation of how specific interactions influence electrode interfaces and electron transfer reactions, extending beyond the intrinsic properties of the electrolyte. These insights have the potential to revolutionize electrolyte design across various electrochemical systems, particularly energy storage technologies that require kinetic advancements.