Crosslinking Nanoarchitectonics of Nitrogen-doped Carbon/MoS₂ Nanosheets/Ti₃C₂T_x MXene Hybrids for Highly Reversible Sodium Storage

Although it is a promising sodium storage material due to its excellent electrochemical activity, small bandgap, and large interlayer spacing, layered molybdenum disulfide (MoS₂) suffers from poor rate capability and degraded cycling life, resulting from its serious aggregation upon preparation, sluggish reaction kinetics, and structure expansion during cycling. To address these issues, a polyethyleneimine (PEI)-assisted fabrication approach was developed for the rational synthesis of an interconnected framework with nitrogen-doped carbon-confined MoS₂ nanosheets/Ti₃C₂T_x MXene (MoS₂/Ti₃C₂T_x@NC), where the PEI could guide the uniform growth of MoS₂ on Ti₃C₂T_x and the self-generated NC simultaneously enhanced its synergistic coupling with MoS₂/Ti₃C₂T_x, thus contributing to the improvement of charge transfer, diffusion kinetics, and structural integrity of the hybrid electrode. Consequently, the desired MoS₂/Ti₃C₂T_x@NC delivered impressive sodium storage performance, demonstrating high reversible capacities of 397.3 and 206.8 mAh g⁻¹ at 0.1 A g⁻¹ after 100 cycles and 0.5 A g⁻¹ after 500 cycles, respectively. Moreover, electrochemical kinetics analysis and charge storage mechanism manifested that high capacitive contribution, facilitated Na⁺ transport pathways, and synergistic electronic coupling between MoS₂/Ti₃C₂T_x and NC contributed to the superior sodium storage performance.