Confined Element Distribution with Structure‐Driven Energy Coupling for Enhanced Prussian Blue Analogue Cathode

Abstract The structural failure of Na 2 Mn[Fe(CN) 6 ] could not be alleviated with traditional modification strategies through the adjustable composition property of Prussian blue analogues (PBAs), considering that the accumulation and release of stress derived from the MnN 6 octahedrons are unilaterally restrained. Herein, a novel application of adjustable composition property, through constructing a coordination competition relationship between chelators and [Fe(CN) 6 ] 4− to directionally tune the enrichment of elements, is proposed to restrain structural degradation and induce unconventional energy coupling phenomenon. The non‐uniform distribution of elements at the M 1 site of PBAs (NFM‐PB) is manipulated by the sequentially precipitated Ni, Fe, and Mn according to the Irving‐William order. Electrochemically active Fe is operated to accompany Mn, and zero‐strain Ni is modulated to enrich at the surface, synergistically mitigating with the enrichment and release of stress and then significantly improving the structural stability. Furthermore, unconventional energy coupling effect, a fusion of the electrochemical behavior between Fe LS and Mn HS , is triggered by the confined element distribution, leading to the enhanced electrochemical stability and anti‐polarization ability. Consequently, the NFM‐PB demonstrates superior rate performance and cycling stability. These findings further exploit potentialities of the adjustable composition property and provide new insights into the component design engineering for advanced PBAs.