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

Metallic 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.