Yuezheng Liu, Jingfu Shi, Yifan Wang, Shengnan He, H. Y. Pan, Zhijun Wu, Yong Wu, Yingying Lu
Anode-free solid polymer electrolytes (AF-SPEs) offer a compelling route to maximize cell-level energy density while improving safety, cost, and manufacturability by replacing the anode with a bare current collector and leveraging ultrathin, low-density polymer membranes. This review explores key design strategies for optimizing SPE performance in anode-free lithium metal batteries (AFLMBs), focusing on their role in regulating lithium deposition, enhancing interfacial stability, and improving electro-chemo-mechanical robustness. It also examines the fundamental strategies for enhancing the performance of AF-SPEs, including polymer chemistry, interfacial engineering, and full-cell lithium inventory management. The review provides insights into the potential of AF-SPEs to maximize the cell-level energy density as well as to drive the commercialization of high-performance, anode-free solid-state batteries.