Anti-freezing electrolyte modification strategies toward low-temperature aqueous zinc-ion batteries

Due to the availability of zinc resources, and reduced security risks, aqueous zinc-ion batteries (AZIBs) are potential contenders for next-generation energy storage systems. With the multi-scene application of AZIBs, the temperature adaptation of electrolytes poses a great challenge. However, the aqueous electrolyte is prone to freezing in sub-zero environments, which leads to undesirable problems such as undesirable ion transfer and poor electrode/electrolyte interface, resulting in a sharp deterioration of the electrochemical properties of AZIBs in cold conditions and limited practical use of AZIBs. Antifreeze electrolyte modification strategies have gained popularity as effective ways to optimise the low-temperature behaviour of AZIB. The results of recent studies of electrolyte modification strategies are systematically summarised for low-temperature AZIBs, focusing on the modification methods, principles, and effects achieved. Firstly, the authors describe the mechanism of failure of AZIBs at low temperatures. Subsequently, the modification strategies of antifreeze electrolytes are summarised, including the utilisation of high salt content, the design of organic electrolytes, the adoption of antifreeze electrolyte additives, and the building of hydrogel electrolytes. Finally, the issues faced by electrolytes at low temperatures are further indicated and suggestions are provided for their future development.