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.