Vertically Oxygen-Incorporated MoS₂ Nanosheets Coated on Carbon Fibers for Sodium-Ion Batteries

Developing a high-performance anode with high reversible capacity, rate performance, and great cycling stability is highly important for sodium-ion batteries (SIBs). MoS₂ has attracted extensive interest as the anode for SIBs. Herein, the vertically oxygen-incorporated MoS₂ nanosheets/carbon fibers are constructed via a facile hydrothermal method and then by simple calcination in air. Oxygen incorporation into MoS₂ can increase the defect degree and expand the interlayer spacing. Vertical MoS₂ nanosheet array coated on carbon fibers not only can expose rich active sites and reduce the diffusion distance of Na⁺, but also improve the electronic conductivity and enhance structural stability. Meanwhile, interlayer-expanded MoS₂ can decrease Na⁺ diffusion resistance and increase accessible active sites for Na⁺. In this work, the electrode combining the oxygen-incorporated strategy with vertical MoS₂ nanosheet-integrated carbon fibers displays high specific capacities of 330 mAh g^-1 over 100 cycles at a current density of 0.1 A g^-1 together with excellent rate behavior as the anode for SIBs. This strategy offers a helpful way for improving the electrochemical performance.