Amorphous MoS3 decoration on 2D functionalized MXene as a bifunctional electrode for stable and robust lithium storage

The development of electrode materials with the synergistic effects of good chemical stability and high electrical conductivity has improved the sluggish ion kinetics and severe capacity degradation of rechargeable lithium batteries. Herein, a multifunctional heterostructure material (MoS3-Ti3C2Tx) comprising a functionalized MXene (Ti3C2Tx) and amorphous MoS3 is prepared by a scalable electrostatic self-assembly method. Remarkably, as lithium-ion battery anodes, the resultant MoS3-Ti3C2Tx not only exhibits increased electrochemical activity, accelerated lithium-ion diffusion and fast charge transfer kinetics but also shows high specific capacity, excellent rate performance and long-term cycling stability. By virtue of these merits, MoS3-Ti3C2Tx offers an excellent reversible capacity of 1043 mAh g−1 at 200 mA g−1 and exhibited a capacity of 568 mAh g−1 at a current density of 2 A g−1 after 1000 cycles. When acting as the cathode for lithium-sulfur batteries, the amorphous MoS3 anchored on MXene demonstrates high capture and catalytic activity towards polysulfide conversion. Accordingly, the optimized electrode exhibits a capacity of 836 mAh g−1 at 0.2C after 100 cycles and a satisfactory rate performance of 463 mAh g−1 at 2C after 400 cycles. Moreover, the associated conversion mechanism is studied by ex situ XPS. These results demonstrate that heterostructure composites constructed by an amorphous sulfide and surface functionalized MXene are feasible electrode materials for both lithium-sulfur batteries and lithium-ion batteries.