Advanced design for anti-freezing aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) have attracted much attention, and are considered to be one of the ideal energy storage devices owing to their safety, environmental friendliness, and low cost. However, their inferior low-temperature performance limits their practical applications. Therefore, improving the low-temperature performance of AZIBs is of great significance. Over the past few years, there is a rapid growing number of publications and citations in the field where some latest advanced design strategies have been proposed for anti-freezing AZIBs such as deep eutectic sol electrolyte and chaotropic salt electrolyte which, however, have not been reviewed. Therefore, a timely review of advanced design strategies for anti-freezing AZIBs is urgently needed. Herein, the latest progress about advanced design strategies for the anti-freezing AZIBs is systematically reviewed. First, we analyze effects of temperature on the performance of battery from the thermodynamic and kinetics factor in depth. Then, we propose three main mechanisms for improving the anti-freezing property of aqueous electrolytes, including breaking the free water hydrogen bonds, confining the free water hydrogen bonds, and reducing the free water content. Afterwards, advanced design strategies for anti-freezing AZIBs are thoroughly summarized from the perspectives of electrolyte optimization and electrode material design. In the end, our perspectives on potential directions are proposed for future development and practical applications of anti-freezing AZIBs.