Nano-sized Titanium Nitride Functionalized Separator Improves Cycling Performance of Lithium Sulfur Batteries

High-energy lithium-sulfur batteries have been plagued by the poor cyclability due to the soluble lithium polysulfide intermediates into the organic electrolyte. Here, we design a separator functionalized by a simple coating of nanosized titanium nitride and super C65. Lithium-sulfur batteries with the functional separator achieve a high specific capacity of 935 mAh g⁻¹ at a current density of 0.5 C, and show a super-long cycling performance at a small degradation rate. The improvement mechanisms introduced by the new separator are further investigated by the electrochemical analysis and theoretical calculation.