Controllable Sulfurization of MXenes to In-Plane Multi-Heterostructures for Efficient Sulfur Redox Kinetics

Although in-plane heterostructure with high ion transport pathway and unique interfacial atomic structure offers endless possibilities in the catalysis field, it is still challenging to directly synthesize MXene-based in-plane heterostructure due to the differences in crystal structures and growth conditions. Here, Mo₂C–MoS₂ in-plane multi-heterostructures are synthesized by topological conversion of sandwich-like mesoporous Mo₂C–SiO₂ layers in sulfur vapor and subsequent removal of SiO₂. During the conversion process, the exposed Mo₂C will efficiently converted to 2H phase MoS₂, meanwhile, the covered Mo₂C remained stable, affording metallic Mo₂C MXene and semiconducting MoS₂ in-plane multi-heterostructures compatible in one layer. The resultant Mo₂C–MoS₂ layer has multiple heterointerfaces, build-in electric fields as well as abundant defects. Such structural features enable to improve of the electrochemical active surface area (16.4 mF cm⁻²), which not only facilitates the bidirectional sulfur electrochemistry between solid Li₂S and soluble lithium polysulfides, but also enhances the transfer kinetics of electrons and ions, giving rise to a high-rate performance (642 mAh g⁻¹ at 5 C) and a long-term cycle life (1000 cycles at 5 C) in lithium–sulfur batteries.