Prussian Blue Analogues Cathodes for Nonaqueous Potassium‐Ion Batteries: Past, Present, and Future

Abstract Recently, potassium‐ion batteries (PIBs) have emerged as a new energy storage system, offering a complementary solution to lithium‐ion batteries due to their cost‐effectiveness and significantly high theoretical energy density, making them suitable for large‐scale grid energy storage applications. The critical challenge PIBs face is the scarcity of appropriate high‐capacity cathode materials. Among the various contenders, Prussian blue analogs (PBAs) stand out. The appeal of PBAs arises from their simple synthesis, economic viability, and a stable, open framework conducive to the insertion/extraction of large‐size K + . This review aims to provide an overview of current research progress on PBAs as cathode materials in nonaqueous PIBs. A comprehensive examination of the crystal structure and electrochemical reaction mechanisms of PBAs is undertaken, with a focus on prevalent optimization strategies in PIBs. Subsequent sections delve into designing and developing potassium‐based full cells architectures incorporating PBAs. The discourse culminates in a discussion on the requirements for transitioning PBAs PIBs from a laboratory setting to commercial production, aiming to chart a course for the development of advanced PIBs.