Enhanced Electrochemical Kinetics and Polysulfide Traps of Bifunctional Perovskite Promoter for Highly Stable Lithium–Sulfur Batteries

Due to the high theoretical energy density, lithium–sulfur batteries have been regarded as one of the secondary cells with promising development prospects. Here, the vacuum filtration is used to prepare multiwalled carbon nanotube/La0.65Sr0.35MnO3(MWCNT/LaSrMn) composite coatings on the Celgard separator to obtain the functional separator, thus achieving a highly stable lithium–sulfur battery. In the polysulfide solution, the presence of O sites and Sr sites forms Li–O bonds and Sr–S bonds respectively, which is more conducive to polysulfide adsorption. Moreover, LaSrMn acts as an intermediate site to accept the deposition of Li2S and promote its uniform spread. The high catalytic properties of LaSrMn can accelerate the redox kinetics of polysulfides. The lithium–sulfur battery with an MWCNT/LaSrMn-Celgard separator exhibits excellent performance. The initial specific capacity of the battery with LaSrMn/MWCNT-Celgard separator is as high as 859.2 mAh g–1. After 500 cycles, the capacity slowly decreases to 730.3 mAh g–1 with a little capacity attenuation rate of only 0.03% per cycle. The capacity is rapidly stabilized at 868 mAh g–1 even after 100 cycles at 60 °C, with a capacity attenuation rate of 0.03% per cycle at 1C.