Self-Assembly of 0D-2D Heterostructure Electrocatalyst from MOF and MXene for Boosted Lithium Polysulfide Conversion Reaction.

The design of nanostructured electrocatalysts with high activity and long-term durability for the sluggish lithium polysulfide (LiPS) conversion reaction is essential for the development of high-performance lithium-sulfur (Li-S) batteries. Here, the self-assembly of bimetallic selenides on nitrogen-doped MXene (CoZn-Se@N-MX) based on the self-assembly of metal-organic framework and MXene is reported. A combination of 0D CoZn-Se nanoparticles and 2D N-MX nanosheet co-catalysts forms double lithiophilic-sulfifilic binding sites that effectively immobilize and catalytically convert LiPS intermediates. This 0D-2D heterostructure catalyst has a hierarchical porous architecture with a large active area and enables rapid Li ion diffusion, reduces the activation energy of Li2 S deposition, and lowers the energy barrier of Li2 S dissolution. In addition, an assembled CoZn-Se@N-MX hybrid synergistically prevents the aggregation of the CoZn-Se nanoparticles and restacking of the active areas of N-MX nanosheets during assembly and the LiPS conversion process. The Li-S battery with this 0D-2D catalyst delivers excellent rate capability, ultralong cycling life (over 2000 cycles), and a high areal capacity of 6.6 mAh cm-2 with a low electrolyte/sulfur ratio of 5 µL mg-1 .