Ar/NH 3 Radio‐Frequency Plasma Etching and N‐doping to Stabilize Metallic Phase 1T‐MoS 2 for Fast and Durable Sodium‐Ion Storage

Abstract Metallic phase 1T‐MoS 2 is considered a prospective anode material for sodium‐ion batteries (SIBs) due to its remarkable electrical conductivity and unique layered structure. However, 1T‐MoS 2 is thermodynamically unstable and prone to phase transition to the 2H‐MoS 2 phase. Herein, self‐supporting nitrogen‐doped and carbon‐coated 1T/2H mixed‐phase MoS 2 nanosheets with rich sulfur vacancies on carbon cloth (C@N‐MoS 2 ‐p/CC) are synthesized through a hydrothermal method and Ar/NH 3 radio‐frequency (RF) plasma treatment process. Density‐functional‐theory (DFT) calculations demonstrate that after Ar/NH 3 RF plasma treatment, nitrogen‐doping and etching effects are realized, which combine with carbon‐coating significantly reduce the phase transition energy of 1T‐MoS 2 , thus triggering the phase transition and enabling the stable existence of the highly active 1T‐MoS 2 . As a result, the C@N‐MoS 2 ‐p/CC exhibits outstanding sodium storage performance, with initial charge–discharge capacities of 701.0/797.0 mAh g −1 at 1 A g −1 , respectively. It also demonstrates exceptional rate capabilities and ultra‐high cyclic stability, maintaining a discharge capacity of 404.2 mAh g −1 after 910 cycles at a high rate of 2 A g −1 . In a full cell with Na 3 V 2 (PO 4 ) 3 /CC cathode, it exhibits excellent initial charge–discharge capacities of 102.3/102.9 mAh g −1 and maintains satisfactory cycling stability after 350 cycles (86.7 mAh g −1 ) at 0.1 C.