Vacancy engineering of MoS2−X @NCNTs for efficient storage of zinc ions

Zinc-ion batteries are receiving interest due to their high level of safety and eco-friendliness. However, the sluggish diffusion kinetics of zinc ions in the electrode limit its practical application. In this paper, rapid Zn 2+ diffusion in the MoS 2−X @NCNTs cathode is achieved by utilizing the S vacancies generated under a H 2 /Ar atmosphere and N-doped carbon nanotubes (NCNTs) derived from the pyrolysis of polyethylene and melamine. The presence of S vacancies significantly reduces the diffusion barrier of Zn 2+ , thereby promoting the transport of Zn 2+ ions. MoS 2−X @NCNTs cathode demonstrates an impressive discharge specific capacity of 220 mAh g −1 (0.1 A g −1 ) and a remarkable reversible capacity of 173 mAh g −1 (3 A g −1 ). Furthermore, the reduced adsorption energy of MoS 2−X nanosheets leads to Zn 2+ tending to preferentially insert S vacancies, resulting in a larger capacity than pure MoS 2 . This work realizes efficient storage of Zn 2+ in 2D disulfides through carbon frameworks and S vacancies. In addition, flexible zinc batteries with MoS 2−X @NCNTs cathodes have promising applications in wearable devices .