Crosslinking Nanoarchitectonics of Nitrogen-doped Carbon/MoS2 Nanosheets/Ti3 C2 Tx MXene Hybrids for Highly Reversible Sodium Storage.

Abstract

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/Ti3 C2 Tx MXene (MoS2 /Ti3 C2 Tx @NC), where the PEI could guide the uniform growth of MoS2 on Ti3 C2 Tx and the self-generated NC simultaneously enhanced its synergistic coupling with MoS2 /Ti3 C2 Tx , thus contributing to the improvement of charge transfer, diffusion kinetics, and structural integrity of the hybrid electrode. Consequently, the desired MoS2 /Ti3 C2 Tx @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 /Ti3 C2 Tx and NC contributed to the superior sodium storage performance.