Two-dimensional molybdenum nitride nanosheets modified Celgard separator with multifunction for LiS batteries

Lithium-sulfur (Li S) batteries are attractive candidates for advanced energy storage devices. However, the low utilization of sulfur and the severe “shuttle effect” hinder the commercialization of Li S batteries. Herein, we design an ultra-thin and lightweight two-dimensional (2D) molybdenum nitride nanosheets layer to modify Celgard (denoted as MoN x /Celgard) separator to promote the electrochemical performance of Li S batteries. Benefiting from the 2D polar molybdenum nitride nanosheets, the obtained molybdenum nitride layer can effectively suppress the shuttle effect via the synergistic effect of structural confinement and chemical absorption . Meanwhile, molybdenum nitride nanosheets layer possesses metallic and catalytic characteristics, which are beneficial for high sulfur utilization. Therefore, the Li S batteries using MoN x /Celgard separator with multifunction exhibit high capacity and outstanding cycling performance. It delivers a high discharge capacity of 1298 mA h g −1 at 0.1C and sustain a capacity of 566 mA h g −1 after 500 cycles at 0.5C, corresponding with the capacity fading rate of only 0.063% per cycle.