Construction of a Sandwich-like Nanostructure by Inserting an Organic Hybrid Antimony Sulfide into rGO/MXene Nanosheets for Enhanced Sodium-Ion Storage Performance

Agglomeration of metal sulfide nanoparticles limits their application as anode materials in sodium-ion batteries (SIBs) because agglomerated nanoparticles not only lengthen the diffusion distance of sodium ions to the internal particles but also increase the intergranular stress during the sodiation process. To settle this issue, constructing specific nanostructures is preferable for dispersing the metal sulfide nanoparticles. Herein, we synthesized an organic hybrid antimony sulfide [1,8-DAOH₂][Sb₄S₇] (DAS), which has a layered structure with an interlayer distance of 7.32 Å. Through a simple ultrasonication and stirring method, DAS nanoparticles were coupled with reduced graphene oxide (rGO) and MXene nanosheets to obtain sandwich-like nanostructured composite DAS@rGO@MXene. Particularly, this sandwich-like nanostructure effectively suppressed the agglomeration of DAS nanoparticles and the restacking of MXene nanosheets. Meanwhile, the anchoring of DAS nanoparticles on the MXene nanosheets improved the conductivity of the composite, and the wrapping of DAS and MXene by rGO nanosheets shortened the transport path of sodium ions. Consequently, the DAS@rGO@MXene electrode delivered a specific capacity of 418.7 mAh g^-1 after 600 cycles at 1.0 A g^-1. In addition, DAS@rGO@MXene exhibited a lower charge-transfer resistance and a faster sodium-ion transport rate as compared with DAS@rGO, DAS@MXene, DAS, and Sb₂S₃ electrodes. Our work provides an idea for designing anode materials based on organic hybrid metal sulfides for SIBs.