Flexible MXene-Ti3C2Tx bond few-layers transition metal dichalcogenides MoS2/C spheres for fast and stable sodium storage

Abstract

The structure collapse and volume expansion of anode materials are the restrictive factors of SIBs industrialization. In this work, monolayer and interlayer-expanded few layers MoS2 are uniformly confined in N-doped carbon matrix and further assembled into hollow hierarchical spheres (H-MoS2@NC). The mono/few layer structured MoS2 is helpful to decrease ion diffusion energy barrier for accelerating electrochemical reaction kinetics. The robust protection carbon layer between the interlayer of MoS2 sheets can not only stabilize the layered structure of MoS2 but also further increase the conductivity of composite, and the hierarchical, porous and hollow structure furnishes a fast electronic migration channels and restrains the volume change of MoS2 during charge and discharge processes. In addition, MXene-Ti3C2Tx sheets are instead of polymer binders to prepare flexible, binder-free electrode (MX-H-MoS2@NC), in which electrons and ions travel faster without the hindrance of polymer binder. Moreover, the flexible MX-H-MoS2@NC electrode can also alleviate the overall volume expansion of H-MoS2@NC spheres. Consequently, the sodium storage property of MX-H-MoS2@NC exhibit the better sodium storage performance than that of PVDF bonded H-MoS2@NC and bare MoS2. Further, the MX-H-WS2@NC with same structure is also synthesized by our proposed method, indicating that this method has universal applicability to fabricate more MXene bonded hollow hierarchical spheres are made of mono layer structured transition metal chalcogenides (MX-H-LTMDs@NC).