Electrolyte Design\nvia Cation–Anion Association\nRegulation for High-Rate and Dendrite-Free Zinc Metal Batteries at\nLow Temperature

Low-temperature zinc metal batteries (ZMBs) are highly\nchallenged\nby Zn dendrite growth, especially at high current density. Here, starting\nfrom the intermolecular insights, we report a cation–anion\nassociation modulation strategy by matching different dielectric constant\nsolvents and unveil the relationship between cation–anion association\nstrength and Zn plating/stripping performance at low temperatures.\nThe combination of comprehensive characterizations and theoretical\ncalculations indicates that moderate ion association electrolytes\nwith high ionic conductivity (12.09 mS cm<sup>–1</sup> at −40\n°C) and a stable anion-derived solid electrolyte interphase (SEI)\njointly account for highly reversible and dendrite-free Zn plating/stripping\nbehavior, resulting in high-rate and ultrastable cycle performance\nat low temperature. As a result, at −40 °C, Zn//Zn cells\ncan stably cycle over 400 h at 5 mA cm<sup>–2</sup> and 10\nmAh cm<sup>–2</sup> and Zn//Cu cells exhibit an exceptional\naverage Coulombic efficiency (CE) of 99.91% for 1800 cycles at 1 mA\ncm<sup>–2</sup> and 1 mAh cm<sup>–2</sup>. Benefiting\nfrom enhanced low-temperature Zn plating/stripping performance, Zn//PANI\nfull cells stably operate for 12,000 cycles at 0.5A g<sup>–1</sup> and 35,000 cycles at 5 A g<sup>–1</sup>. Impressively, at\n−60 °C, Zn//Cu cells still display a high average CE of\n99.68% for 2000 cycles. This work underscores the crucial effect of\ncation–anion association regulation for high-rate and dendrite-free\nZn metal anodes, deepening the understanding of intermolecular interaction\ninsights for low-temperature electrolyte design.