The discovery of interfacial electronic interaction within cobalt boride@MXene for high performance lithium-sulfur batteries

Lithium-sulfur battery is strongly considered as the most promising next-generation energy storage system because of the high theoretical specific capacity. The serious shuttle effect and sluggish reaction kinetic limited the commercial application of lithium-sulfur battery. Many heterostructures were applied to accelerate polysulfides conversion and suppress their migration in lithium-sulfur batteries. Nevertheless, the effect of the interface in heterostructure was not clear. Here, the Co2B@MXene heterostructure is synthesized through chemical reactions at room temperature and employed as the interlayer material for Li-S batteries. The theoretical calculations and experimental results indicate that the interfacial electronic interaction of Co2B@MXene induce the transfer of electrons from Co2B to MXene, enhancing the catalytic ability and favoring fast redox kinetics of the polysulfides, and the theoretical calculations also reveal the underlying mechanisms for the electron transfer is that the two materials have different Fermi energy levels. The cell with Co2B@MXene exhibits a high initial capacity of 1577 mAh/g at 0.1 C and an ultralow capacity decay of 0.0088% per cycle over 2000 cycles at 2 C. Even at 5.1 mg/cm(2) of sulfur loading, the cell with Co2B@MXene delivers 5.2 mAh/cm(2) at 0.2 C. (C) 2021 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

The Co2B@MXene heterostructure shows enhanced performance as an interlayer material for lithium-sulfur batteries, achieving high initial capacity and low capacity decay rate. The interfacial electronic interaction facilitates electron transfer, enhancing catalytic ability and redox kinetics.