Dendrite-free electrolyte for Zn/LiFePO4 batteries operating at low-temperature

Zinc-ion batteries, known for safety and efficiency, are a hotspot in electrochemical energy storage field. Nonetheless, the emergence of dendrites on zinc anodes during electrochemical cycles can lead to capacity attenuation and even failure, particularly under low temperatures. In this study, we develop a novel dendrite-free and low-temperature resistant Zn(ClO4)2/Li2SO4/Dimethyl sulfoxide (DMSO) hybrid electrolyte by using DMSO as a hydrogen bond acceptor and solvation regulator. Our research demonstrates that, by reducing the desolvation energy barrier of the Zn2+ solvation sheath and the nucleation overpotential of Zn deposition, DMSO effectively inhibits zinc dendrites and side reactions. Furthermore, DMSO disrupts hydrogen bonding between water molecules, preventing electrolyte freezing at low temperatures. As a result, at 0.5 mA cm−2, the Zn||Zn symmetric device using this hybrid electrolyte exhibits consistent operation for over 4000 hours even at -25 °C, featuring a minimal deposition/dissolution overpotential of approximately 0.045 mV. Additionally, at -20 °C, the Zn||Zn(ClO4)2-Li2SO4-DMSO||LiFePO4 battery demonstrates stable cycling for over 600 cycles at 0.6 C (1 C = 170 mA g−1), delivering a capacity of 103 mA h g−1.