Mechanistic Insights into the Structural Modulation of Transition Metal Selenides to Boost Potassium Ion Storage Stability

Atomic-level structure engineering is an effective strategy to reduce mechanical degradation and boost ion transport kinetics for battery anodes. To address the electrode failure induced by large ionic radius of K⁺ ions, herein we synthesized Mn-doped ZnSe with modulated electronic structure for potassium ion batteries (PIBs). State-of-the-art analytical techniques and theoretical calculations were conducted to probe crystalline structure changes, ion/electron migration pathways, and micromechanical stresses evolution mechanisms. We demonstrate that the heterogeneous adjustment of the electronic structure can relieve the potassiumization-induced internal strain and improve the structural stability of battery anodes. Our work highlights the importance of the correlation between doping chemistry and mechanical stability, inspiring a pathway of structural engineering strategy toward a highly stable PIBs.