Recent Advances for Cation-Anion Aggregates in Solid Polymer Electrolytes: Mechanism, Strategies, and Applications

Solid polymer electrolytes (SPEs) have garnered significant attention from both academic and industrial communities due to their high safety feature and high energy density in combination with lithium(Li) metal anode. Nevertheless, their practical applications remain constrained by the relatively low room-temperature ionic conductivity and interface issues. Anion-derived cation-anion aggregates (AGGs), derived from high-concentration liquid electrolytes, promote a stable solid-electrolyte interphase layer, which have gradually propelled their application in SPEs. Meanwhile, the unique ion transport mechanism of AGGs in SPEs also helps to enhance their ionic conductivity. However, the detail mechanism and the application progress of AGGs in SPEs remain poorly understood. Here, it is begin with a concise historical review on the development of AGGs configuration, followed by discussion on the fundamental mechanisms of the ion transport in AGGs-based SPEs. Then, focused on the recent developments, the design strategies for AGGs-based SPEs are summarized in detail. Finally, perspectives are provided on the future developments and challenges for high-performance AGGs-based SPEs.