2D MoN-VN Heterostructure To Regulate Polysulfides for Highly Efficient Lithium-Sulfur Batteries.

Lithium-sulfur batteries hold promise for next-generation batteries. A problem, however, is rapid capacity fading. Moreover, atomic-level understanding of the chemical interaction between sulfur host and polysulfides is poorly elucidated from a theoretical perspective. Here, a two-dimensional (2D) heterostructured MoN-VN is fabricated and investigated as a new model sulfur host. Theoretical calculations indicate that electronic structure of MoN can be tailored by incorporation of V. This leads to enhanced polysulfides adsorption. Additionally, in situ synchrotron X-ray diffraction and electrochemical measurements reveal effective regulation and utilization of the polysulfides in the MoN-VN. The MoN-VN-based lithium-sulfur batteries have a capacity of 708 mA h g-1 at 2 C and a capacity decay as low as 0.068 % per cycle during 500 cycles with sulfur loading of 3.0 mg cm-2 .