INSIGHTS INTO HIGH ENTROPY PRUSSIAN BLUE ANALOGUE BATTERIES: LATTICE MECHANISMS, SYNTHESIS AND ENHANCEMENT

Prussian Blue Analogues (PBAs) are rising as popular energy storage materials due to their open, face-centred cubic lattice and tunable electrochemical properties. In particular, high-entropy PBAs (HE-PBAs), of general formula AₓM₂[M₁(CN)₆]ᵧ·nH₂O (0 ≤ x ≤ 2, 0 ≤ y ≤ 1), leverage a multicomponent lattice stability and enhanced performance with mixed‐valence metal centers to stabilize the host structure, homogenize cation distribution, and optimize ion-transport channels. This review compiles recent advances in low-cost, scalable synthesis methods—including co-precipitation and other methods employed for enhancement of the battery's performance, such as vacancy engineering and carbon coating, additionally providing a comparison on the specific capacity and retention of the materials with work from other experiments. Analysis of X-ray diffraction and microscopy in various studies reveals how lattice vacancies, surface modifications, and framework substitutions influence electronic conductivity and ion diffusivity. Across reported studies, HE-PBAs consistently deliver enhanced electrochemical performance, exhibiting high reversible capacities, rapid charge–discharge rates, with easily preparable materials and cost-effective methods with procurable components, positioning them as strong candidates for commercial and grid-scale energy storage, for which future research is encouraged.