The Progress of Polymer Composites Protecting Safe Li Metal Batteries: Solid‐/Quasi‐Solid Electrolytes and Electrolyte Additives

The impressive theoretical capacity and low electrode potential render Li metal anodes the most promising candidate for next‐generation Li‐based batteries. However, uncontrolled growth of Li dendrites and associated parasitic reactions have impeded their cycling stability and raised safety concerns regarding future commercialization. The uncontrolled growth of Li dendrites and associated parasitic reactions, however, pose challenges to the cycling stability and safety concerns for future commercialization. To tackle these challenges and enhance safety, a range of polymers have demonstrated promising potential owing to their distinctive electrochemical, physical, and mechanical properties. This review provides a comprehensive discussion on the utilization of polymers in rechargeable Li‐metal batteries, encompassing solid polymer electrolytes, quasi‐solid electrolytes, and electrolyte polymer additives. Furthermore, it conducts an analysis of the benefits and challenges associated with employing polymers in various applications. Lastly, this review puts forward future development directions and proposes potential strategies for integrating polymers into Li metal anodes. The use of polymer materials in Li metal batteries has the potential to achieve long‐term stability. Polymers are becoming increasingly important in flexible electrodes, solid‐state electrolytes, separators, and artificial SEI layers. In this review, we analyzed the differences in the composition of various polymers used in Li metal batteries and discussed the future of polymer materials.