Rational design of MXene-MoS2 heterostructure with rapid ion transport rate as an advanced anode for sodium-ion batteries

Molybdenum disulfide (MoS2) has attracted great attention as a promising material for sodium (Na)-ion batteries (SIBs) due to its high theoretical capacity and unique layered structure. However, the intrinsic poor electrical conductivity and uncontrollable volume change of the pristine MoS2 during the ion insertion/extraction process result in its low rate performance and rapid capacity fading. Considering that the migration path length of the ion determines its diffusion time, shortening it can further increase the diffusion rate, thereby realizing fast Na ion storage. Herein, we prepare an interconnected network heterostructure consisting of small-sized MoS2 anchored on nitrogen-doped MXene substrates (MXene-MoS2). The as-prepared MXene-MoS2 heterostructure not only enhances the electrical conductivity and structural stability of the electrode materials but also reduces the Na ion diffusion length to achieve rapid Na ion transport kinetics. Meanwhile, the robust heterointerface guarantees fast and unimpeded electron transfer channels, thereby improving the electrochemical reaction kinetics. As a consequence, the MXene-MoS2 delivers an excellent reversible capacity of 315 mAh g−1 at 0.2 A g−1 and 220.0 mAh g−1 after 1000 cycles at 2.0 A g−1. This study may provide the possibility for the practical application of the MXene-MoS2 as a SIB anode.