Mn-based layered oxides are widely considered as cost-effective cathodes for K-ion batteries (KIBs), whereas the local lattice distortion induced by the Jahn-Teller effect of Mn³⁺ usually results in limited capacity and unsatisfactory cycling lives. Herein, a new P3-type K_0.45Mn_0.9Al_0.1O₂ material is designed via riveting electrochemical inactive Al³⁺ in the octahedral Mn³⁺ sites, which is experimentally proved to play a key role in suppressing misfit dislocations at the atomic scale, enlarging the spacing of K⁺ layers, relieving exothermic phase transition at elevated temperature and helping to form a stable and uniform cathode electrolyte interphase (CEI) layer synergistically. Thanks to these inherent merits, K_0.45Mn_0.9Al_0.1O₂ delivers a high specific capacity of 152 mAh/g at 20 mA g⁻¹ and excellent cyclic performance with capacity retention of 67 % over 1000 cycles, much superior to K_0.45MnO₂. Impressively, the full battery achieves a high energy (291 Wh kg⁻¹) and power (843 W kg⁻¹) densities over state-of-the-art layered cathodes for KIBs. This study not only provides a facile and effective strategy to jointly enhance the structural, thermal and interfacial stability of Mn-based layered cathodes, but also the underlying mechanism revealed here sheds light on designing novel cathodes via tailoring the local structural environments.

Mn基层状氧化物被广泛认为是具有成本效益的K离子电池（KIBs）正极，而由Mn ³⁺的Jahn-Teller效应引起的局部晶格畸变通常导致容量有限和循环寿命不理想。在此，通过在八面体Mn ^{3+位点铆接电化学惰性Al 3+}设计了一种新型P 3 型K _0.45 Mn _0.9 Al _0.1 O ₂材料，实验证明该材料在抑制原子错配位错中起关键作用。尺度，扩大K ^+的间距层，缓解高温下的放热相变，并协同形成稳定且均匀的阴极电解质界面 (CEI) 层。由于这些固有的优点，K _0.45 Mn _0.9 Al _0.1 O ₂在 20 mA g ^-1下具有 152 mAh/g 的高比容量和出色的循环性能，在 1000 次循环中容量保持率为 67 %，远优于 K _0.45 MnO ₂ . 令人印象深刻的是，完整的电池实现了高能量 (291 Wh kg ^-1 ) 和功率 (843 W kg ^-1) 在 KIB 的最先进的层状阴极上的密度。该研究不仅提供了一种简便有效的策略来共同提高 Mn 基层状正极的结构、热和界面稳定性，而且这里揭示的潜在机制为通过调整局部结构环境设计新型正极提供了启示。