A hierarchical nano-MoS flake/micro-MXene lamellar complex structure within a carbon coating for rapid sodium-ion storage

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2024-03, Vol.12 (11), p.6329-634
• Main Authors: Wen, Bingjie, Kong, Nizao, Huang, Min, Fu, Liqin, Tian, Yexin, Liu, Zhixiao, Wang, Zhongchao, Yang, Lezhi, Han, Fei
• Format: Article
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta08010b

A single two-dimensional material often struggles to satisfy all the performance requirements of electrode materials for sodium-ion batteries. However, constructing a hierarchical heterogeneous two-dimensional stacking structure can effectively combine the advantages of multiple materials and make up for the insufficiency of a single element. This work applied a pre-intercalation-sulphuration concept and liquid-phase coating modification by constructing a hierarchical nano-flake/micro-lamellar complex structure. In this composite material, MoS 2 nanosheets and V 2 C MXene layers overlap and interact to prevent nanoparticle agglomeration and micron flakes collapse simultaneously. The MoS 2 /MXene hierarchical structure is sandwiched between ultrathin and dense carbon layers to form a multifaceted conductive skeleton and a twofold protection mechanism. The coating reduces the electrolyte contact area and prevents the escape of polysulfide byproducts. Accordingly, the designed MSVC@C demonstrates superior Na + storage capacities (612.4 mA h g −1 at 0.5 A g −1 after 600 cycles) and outstanding rate performance (304.42 mA h g −1 at 10 A g −1 ). Experimental results and theoretical calculations verify that the MoS 2 and V 2 C heterostructure promotes the electrochemical performance owing to the better electronic conductivity and lower ion diffusion energy barrier. Moreover, this structure optimization strategy applies to various MXene guests ( e.g. , V 2 C and Nb 2 C) to prepare a variety of hierarchical nano-micro structures that are expected to be promising two-dimensional electrode materials for SIBs with application prospects in the future. A hierarchical nano-MoS 2 /micron-MXene composite is designed by a pre-intercalation-sulphuration concept and a polypyrrole-derived carbon "protective framework". The MSVC@C anode exhibits a high capacity and a prominent rate performance for SIBs.