Electron-Injection-Engineering Induced Phase Transition toward Stabilized 1T-MoS2 with Extraordinary Sodium Storage Performance

Phase transition engineering, with the ability to alter the electronic structure and physicochemical properties of materials, has been widely used to achieve the thermodynamically unstable metallic phase MoS2 (1T-MoS2), although the complex operating conditions and low yield of previous strategies make the large-scale fabrication of 1T-MoS2 a big challenge. Herein, we report a facile electron injection strategy for phase transition engineering and fabricate a composite of conductive TiO chemically bonded to 1T-MoS2 nanotlowers (TiO-1T-MoS2 NFs) on a large scale. The underlying mechanism analysis reveals that electron-injection-engineering triggers a reorganization of the Mo 4d orbitals and results in a 100% phase transition of MoS2 from 2H to IT. In the TiO-1TMoS(2) NFs composite, the 1T-MoS2 demonstrates a higher electronic conductivity, a lower Na+ diffusion barrier, and a more restricted S release than 2H-MoS2. In addition, conductive TiO bonding successfully resolves the stability challenge of the IT phase. These merits endow TiO-1T-MoS2 NFs electrodes with an excellent rate capability (650/288 mAh g(-1) at 50/20 000 mA g(-1), respectively) and an outstanding cyclability (501 mAh at 1000 mA after 700 cycles) in sodium ion batteries. Such an improvement signifies that this facile and scalable phase-transition engineering combined with a deep mechanism analysis offers an important reference for designing advanced materials for various applications.

Automated summary

Through electron injection engineering, a reorganization of Mo 4d orbitals is triggered, resulting in a 100% phase transition of MoS2 from 2H to 1T. The composite of TiO-1T-MoS2 NFs demonstrates higher electronic conductivity, lower Na+ diffusion barrier, and more restricted S release compared to 2H-MoS2. The stable bonding of conductive TiO successfully improves the stability of the IT phase, leading to excellent rate capability and outstanding cyclability of the TiO-1T-MoS2 NFs electrodes in sodium ion batteries.