Sustainable All‐Mn‐Based Layered Cathode with Dynamic Structural Stability for Durable Sodium‐Ion Batteries

Abstract

ABSTRACT Layered sodium all‐Mn‐based oxide materials are confronted with irreversible dynamic structural degradation induced by [MnO 6 ] layers gliding and Jahn–Teller (J–T) distortion of high‐spin Mn 3+ during cycling. Although conventional strategies often focus primarily on reducing Mn 3+ content in the pristine material, we reveal that such static valence control is insufficient to ensure long‐term structural integrity. Instead, we demonstrate that dynamic structural regulation effectively decouples the Mn oxidation state changes from degradation pathways. By designing a P’2‐type [Na 0.64 Zn 0.07 ]Mn 0.92 Cu 0.08 O 2 (NZMCO) cathode, which maintains the same initial Mn oxidation state as Na 0.67 MnO 2 (NMO), we achieve exceptional cycling stability via a hierarchical damping‐like mechanism. The designed framework integrates two synergistic stabilization pathways: (i) intralayer coordination tuning by counterbalancing Mn─O bond anisotropy, and (ii) interlayer electrostatic shielding to alleviate gliding between adjacent [MnO 6 ] layers. This strategic configuration effectively alleviates lattice strain and stress accumulation, suppresses microcrack formation, and significantly reduces transition metal dissolution. Consequently, NZMCO delivers a high specific capacity of 194.95 mAh g −1 at 20 mA g −1 , retaining 87.53% of its initial capacity after 1500 cycles at 2000 mA g −1 . This work shifts the design paradigm from static Mn valence engineering toward dynamic structural adaptation, offering a sustainable pathway for all‐Mn‐based layered cathodes.