Enabling low-temperature aqueous zinc/copper-sulfur hybrid batteries through electrolyte design.

Zhou, Haichuan; Hu, Linyu; Liu, Guoqiang; Pi, Yourui; Wan, Fang; Liu, Ying; Wang, Fei; Dai, Chunlong et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Rechargeable aqueous batteries show promise for large-scale energy storage, yet suffer from low specific energy and poor low-temperature performance. Existing low-temperature aqueous batteries typically use ion-insertion positive electrodes with limited capacity. While aqueous sulfur-based batteries offer high theoretical capacity, their low-temperature operation remains challenging. Current improvement strategies often compromise room-temperature performance due to the inclusion of non-active additives. Here, we present a low-temperature sulfur-based battery using a Cu(BF<sub>4</sub>)<sub>2</sub>-based electrolyte, which boasts a low glass transition temperature of -115.1 °C, and an ionic conductivity of 5.16 mS cm<sup>-1</sup> at -60 °C. This electrolyte enables faster reaction kinetics and higher overall specific energy than traditional CuSO<sub>4</sub>-based systems. The resulting zinc-sulfur battery delivers a discharge capacity of 348 mA h g<sub>(S+Zn)</sub><sup>-1</sup>and an specific energy of 339 W h kg<sub>(S+Zn)</sub><sup>-1</sup> at -50 °C, based on the total mass of both the positive and negative electrodes, competitive with existing aqueous batteries.