Alleviating the shuttle effect via bifunctional MnFe2O4/AB modified separator for high performance lithium sulfur battery

Lithium sulfur battery has been regarded as a promising candidate for the next generation advanced energy storage system with the merits of remarkably high energy density, low cost and natural abundance of elemental sulfur. However, the commercialization application of Li-S battery is severely restricted by the intrinsic poor conductivity of sulfur, dissolution of polysulfide as well as the well-known shuttle effect. Herein, binary transition metal oxide manganese ferrite (MnFe2O4) prepared by coprecipitation was successfully used to modify the polypropylene (PP) separator for the first time. The bifunctional modified separator decorated with MnFe2O4 and conductive acetylene black (AB) can efficiently hinder the diffusion of polysulfides due to synergistic effect of effective chemical adsorption and auxiliary physical blocking. Consequently, the cells with modified separator exhibit outstanding rate capacities of 920mAh/g at 1C, 845mAh/g at 2C and superior cycling performance of 625mAh/g after 500 cycles at 1C with a low capacity decaying of 0.074% per cycle. To the best of our knowledge, this work not only firstly testifies that MnFe2O4 could entrap the polysulfide and alleviate the shuttle effect, but also presents a novel strategy by modifying separator with binary metal oxide to enhance the rate capacity and cycle performance of Li-S battery.