Recent Advances in Polymer Electrolytes for Zinc Ion Batteries: Mechanisms, Properties, and Perspectives

Aqueous rechargeable zinc ion batteries (ZIBs) have been deemed to be possible candidates for large-scale energy storage due to their ecoefficiency, substantial reserve, safety, and low cost. However, the challenges inherent in aqueous electrolytes, such as water splitting reactions, water evaporation, and liquid leakage, have greatly hindered their development in energy storage. Fortunately, polymer electrolytes would be able to overcome the abovementioned challenges. Moreover, the flexible properties of polymer electrolytes can facilitate their future application in wearable electronics. Recently, increasing attention has been attracted to the polymer electrolyte-based zinc ion batteries. However, the development of polymer electrolytes for ZIBs is still in the early stages due to numerous challenges. Therefore, substantial research effort is required to overcome the challenges of polymer electrolyte-based ZIBs. In this review, the current progress in developing polymer electrolytes, including solid polymer electrolytes, gel polymer electrolytes, and hybrid polymer electrolytes, as well as the interactions between electrodes and polymer electrolytes for ZIBs is comprehensively reviewed, analyzed, and discussed in terms of their synthesis, characterization, and performance validation. To facilitate further research and development of polymer electrolytes for ZIBs, the relevant challenges are summarized and analyzed, and some underlying approaches to overcome these challenges are also proposed.