Ultrathin two-dimensional bimetal NiCo-based MOF nanosheets as ultralight interlayer in lithium-sulfur batteries

Lithium-sulfur batteries as one of the most promising next-generation high-energy storage system, the shuttle effect, the expansion of cathode and the slow electrode redox kinetics limit its further develop-ment. Herein, we report a two-dimensional, ultrathin and ultra-light bimetal-NiCo-organic framework as the interlayer for Li-S batteries. This kind of interlayer can effectively block polysulfides and accelerate the conversion with a thickness of only 1 mu m and a load of 0.1 mg/cm2. Because the MOF nanosheets with a thickness of a few nanometers have a large specific surface and a large number of exposed ac-cessible active sites. At the same time, the intrinsic activity of each site is enhanced and the catalytic performance is improved due to the synergistic effect of mixed metals and the unique coordination envi-ronment around the active sites. So, 2D NiCo MOF/CNT totally meets the requirements for the lightweight and effective interlayer. The initial discharge capacity of cell with 2D NiCo MOF/CNT interlayer can reach 1132.7 mAh/g at 0.5 C. It remained 709.1 mAh/g after 300 cycles, showing good cycling stability and rate performance. (c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

Here, we report a two-dimensional, ultrathin and ultra-light bimetal-NiCo-organic framework as the interlayer for Lithium-sulfur batteries. This interlayer effectively blocks polysulfides and accelerates their conversion. The electrochemical performance of the batteries is significantly improved with high initial discharge capacity and good cycling stability.