Expanding the low-temperature and high-voltage limits of aqueous lithium-ion battery

Despite strong interest in replacing the flammable non-aqueous electrolytes with an aqueous alternative, the state-of-the-art aqueous electrolytes face challenges in achieving wide electrochemical stability window (ESW) and simultaneously maintaining fast ion-transport at sub-zero temperatures. Here, we proposed a non-flammable hybrid electrolyte consisting of water and 1,3-dioxolane (DOL) with an ESW of 4.7 V that supports fast ion-transport at temperatures as low as -50 °C. DOL-presence reduces the population of free water at anode/electrolyte interface, promoting the formation of a compact LiF-rich interphase, while its weak coordination with Li+ enables fast Li+-desolvation process at low temperatures. LiMn2O4/Li4Ti5O12 lithium-ion batteries containing developed electrolyte demonstrated high Coulombic efficiency (99.8%) for thousands of cycles at room temperature, and remain operational at -50 °C, far outperforming the counterparts using non-aqueous or aqueous electrolytes.