A novel strategy for high-stability lithium sulfur batteries by in situ formation of polysulfide adsorptive-blocking layer

Lithium sulfur (Li[sbnd]S) batteries are one of the most promising energy storage devices owing to their high energy and power density. However, the shuttle effect as a key barrier hinders its practical application by resulting in low coulombic efficiency and poor cycling performance. Herein, a novel design of in situ formed polysulfide adsorptive-blocking layer (PAL) on the cathode surface was developed to tame the polysulfide shuttling and promote the cycling stability for Li[sbnd]S batteries. The PAL is consisted of La₂S₃, which is capable to chemically adsorb polysulfide via the strong interaction of La[sbnd]S bond and S[sbnd]S bond, and build an effective barrier against sulfur escaping. Moreover, the La₂S₃ is capable to suppress the crystallization of Li₂S and promote the ion transfer, which contributes to the reduced internal resistance of batteries. Furthermore, the by-product LiNO₃ simultaneously forms a stable anode solid and electrolyte interface to further inhibit the polysulfide shuttle. By this simple and convenient method, the resultant Li[sbnd]S batteries achieved exceptional cycling stability with an ultralow decay rate of 0.055% since the 10th cycle.