A Separator with Double Coatings of Li4Ti5O12and Conductive Carbon for Li‐S Battery of Good Electrochemical Performance

Abstract

AbstractThe market demand for energy pushes researchers to pay a lot of attention to Li‐S batteries. However, the ‘shuttle effect’, the corrosion of lithium anodes, and the formation of lithium dendrites make the poor cycling performances (especially under high current densities and high sulfur loading) of Li‐S batteries, which limit their commercial applications. Here, a separator is prepared and modified with Super P and LTO (abbreviation SPLTOPD) through a simple coating method. The LTO can improve the transport ability of Li+cations, and the Super P can reduce the charge transfer resistance. The prepared SPLTOPD can effectively barrier the pass‐through of polysulfides, catalyze the reactions of polysulfides into S2−, and increase the ionic conductivity of the Li‐S batteries. The SPLTOPD can also prevent the aggregation of insulating sulfur species on the surface of the cathode. The assembled Li‐S batteries with the SPLTOPD can cycle 870 cycles at 5 C with the capacity attenuation of 0.066% per cycle. When the sulfur loading is up to 7.6 mg cm−2, the specific discharge capacity at 0.2 C can reach 839 mAh g−1, and the surface of lithium anode after 100 cycles does not show the existence lithium dendrites or a corrosion layer. This work provides an effective way for the preparation of commercial separators for Li‐S batteries.