Sulfur‐Anion‐Modulated Electron Configuration of Manganese Selenide for High Performance Sodium Ion Storage

ABSTRACT Manganese selenide (MnSe), as a typical electrode material, has garnered significant attention due to its high theoretical specific capacity and cost‐effectiveness. However, persistent challenges, including sluggish reaction kinetics and inadequate cycling stability, remain to be addressed. Anion‐doping‐induced defect engineering is regarded as a promising strategy to achieve superior sodium storage performance by modulating the electronic configuration of MnSe. In this work, electronegative sulfur (S) is incorporated into nitrogen‐rich metal‐organic framework‐derived MnSe via sulfuration treatment. Various characterizations and theoretical calculations reveal that doping of S into the MnSe lattice can introduce defect levels, optimize ion diffusion pathways, and reduce Na ⁺ diffusion barrier, thereby enhancing the electrochemical performance of the MnSe anode. As expected, the optimal material exhibits excellent rate performance and long‐term cyclability, delivering a specific capacity of 402.7 mAh g ⁻¹ at 2.0 A g ⁻¹ after 300 cycles and retaining 353.1 mAh g ⁻¹ after 800 cycles at 5.0 A g ⁻¹ . Furthermore, ex situ X‐ray diffraction patterns and X‐ray photoelectron spectroscopy are employed to analyze the sodium storage mechanism.