MoS2@C with S vacancies vertically anchored on V2C-MXene for efficient lithium and sodium storage

Abstract

Molybdenum sulfide (MoS₂) with a high theoretical capacity and large interlayer distance has triggered extensive attention as a promising alternative anode for lithium ion batteries (LIBs) and sodium ion batteries (SIBs). However, the sluggish kinetics and structural collapse induced by its poor conductivity usually lead to unsatisfactory rate capability and poor cycling performance. Herein, few-layered MoS₂ with abundant S vacancies were anchored on V₂C-MXene and embedded in carbon via an in situ assembly and carbonization strategy. The V₂C-MXene substrate suppressed the agglomeration and stacking of MoS₂ nanosheets, facilitated the efficient exposure of MoS₂ and shortened the diffusion pathways, which favored ion accessibility and induced a strong capacitive-controlled charge storage behavior. Experimental results and theoretical calculations revealed that the electronic coupling between MoS₂ and V₂C-MXene not only induced abundant S vacancies and modulated the charge distribution but also promoted Li/Na adsorption and lowered the ion diffusion energy barrier. Consequently, the V₂C-MXene coupled MoS₂@C electrode delivered high capacities of 732.8 and 337.3 mA h g⁻¹ at 1 A g⁻¹ in LIBs and SIBs, respectively. This work provided a new insight into the rational design of stable and advanced electrode materials for energy storage and conversion.