Entropically Stabilized Compositionally Complex Prussian Blue Analogues in Electrochemical Energy Storage and Catalytic Applications

ABSTRACT High performance robust electrodes are demanding for next‐generation energy storage devices, especially to raise the energy density and cycle life of rechargeable batteries. Prussian Blue Analogues (PBAs), a class of framework materials possessing a 3D structure have gained vast interest as battery electrodes due to a rich and multiple redox active sites offering tunable chemistry to reversibly store charges. Albeit the Jahn–Teller distortions, structural phase transitions, low electronic conductivity, and lattice degradation certainly restrict the practicality of PBAs, requiring a rational engineering to exploit their properties. This review exclusively focuses on engineering the physical‐chemical‐electrochemical properties of PBA via high configurational entropy and the role of HE‐PBA toward activating the redox centers and improving the structure, cycle stability, and conductivity are elaborated. The entropically tuned HE‐PBAs endow synergistic “cocktail effect” benefitting structural robustness, alleviated/controlled phase transitions, multi‐electron redox activity, and performance improvements in batteries including lithium‐ion (Li‐ion), sodium‐ion (Na‐ion), lithium‐sulfur (Li‐S) and zinc‐ion (Zn‐ion) chemistries and catalytic conversion reactions. Further, the structure‐property relationship of HE‐PBAs in energy storage and catalytic systems are systematically discussed underpinning the role of redox elements in capacity retention, structural stability, phases transition, and cycle‐life. Alongside, a prospect on the practical outcomes and scope for further improvements are detailed.