History of Solid Polymer Electrolyte‐Based Solid‐State Lithium Metal Batteries: A Personal Account

Solid‐state lithium metal batteries (SSLMBs) are believed to be important pathway to overcome the limitations that state‐of‐the‐art lithium‐ion batteries face in terms of safety and energy density. In addition to transporting ionic species in solid‐state configuration, solid polymer electrolytes (SPEs) are structurally designable and processable, and have been deemed as an auspicious kind of solid electrolyte to access highly‐performant SSLMBs. In this essay, we provide a historical overview on the development of SPE‐based SSLMBs, aiming to highlight the main achievements being made at both material and cell levels. It is hoped that the personal reflection and retrospect presented in this essay give an impetus to inspire the discovery of tantalizing battery materials and improve the overall performance of SPE‐based SSLMBs and other emerging battery technologies.