Ar/NH3 Radio‐Frequency Plasma Etching and N‐doping to Stabilize Metallic Phase 1T‐MoS2 for Fast and Durable Sodium‐Ion Storage

Abstract

AbstractMetallic phase 1T‐MoS2 is considered a prospective anode material for sodium‐ion batteries (SIBs) due to its remarkable electrical conductivity and unique layered structure. However, 1T‐MoS2 is thermodynamically unstable and prone to phase transition to the 2H‐MoS2 phase. Herein, self‐supporting nitrogen‐doped and carbon‐coated 1T/2H mixed‐phase MoS2 nanosheets with rich sulfur vacancies on carbon cloth (C@N‐MoS2‐p/CC) are synthesized through a hydrothermal method and Ar/NH3 radio‐frequency (RF) plasma treatment process. Density‐functional‐theory (DFT) calculations demonstrate that after Ar/NH3 RF plasma treatment, nitrogen‐doping and etching effects are realized, which combine with carbon‐coating significantly reduce the phase transition energy of 1T‐MoS2, thus triggering the phase transition and enabling the stable existence of the highly active 1T‐MoS2. As a result, the C@N‐MoS2‐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 Na3V2(PO4)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.