Electron Modulated and Phosphate Radical Stabilized 1T‐Rich MoS2 for Ultra‐Fast‐Charged Sodium Ion Storage

Abstract

AbstractMetallic phase molybdenum sulfide (1T‐MoS2) is considered as an attractive electrode material for sodium‐ion batteries (SIBs) owing to its abundant active sites, metallic conductivity and high theoretical capacity. Unfortunately, the thermodynamic unstable characteristic under natural conditions makes 1T‐MoS2 difficult to synthesize directly, which greatly hinders its further applications. Herein, an electron modulated and phosphate radical stabilized strategy is employed to construct stable 1T‐rich MoS2 (1T‐P‐MoS2). The PO43− groups are intercalated into MoS2 via a simple one‐step synthesis process, which enlarges the interlayer spacings and improves the insertion/extraction kinetics of Na+. Density functional theory (DFT) calculations and experiments demonstrate that the PO43− can give partial electrons to Mo upon PO43− intercalation, which triggers the reorganization of Mo 4d orbitals, resulting in a spontaneous phase transition of MoS2 from 2H to 1T phase, thereby enhancing the electrical conductivity of MoS2. The obtained 1T‐P‐MoS2 exhibits ultra‐fast charged properties (up to 277.1 mAh g−1 at 40 A g−1, discharged/charged within 25 s) and excellent cycling performance (up to 498.9 mAh g−1 after 300 cycles at 1 A g−1). This work provides a feasible technical solution and analyses the deep mechanisms on tuning of metal sulfide electrodes for advanced SIBs.