High performance lithium-sulfur batteries with facile titanium nitride particles modified separator

Rechargeable lithium-sulfur (Li-S) batteries are considered as one of the most potential energy storage devices owing to their high theoretical capacity, environmental friendliness and low cost. However, the practical applications of Li-S batteries are restricted by the low conductivity of sulfur, serious dissolution of intermediate polysulfides and fast capacity degradation. Herein, we design a titanium nitride (TiN) modified separator to improve the long-term cycle stability and discharge capacity of Li-S batteries. Strong interaction between the TiN particles and polysulfides can greatly restrain the “shuttle effect” and benefit the cycle stability. With this modified separator, cathodes with a sulfur loading of 78.1% could deliver a high initial discharge capacity of 1296 mAh/g and demonstrate a decay rate of 0.17% per cycle under a high current density of 0.5C. Such superior electrochemical performances ascribe to the high conductivity of TiN and strong affinity between TiN particles and polysulfides.