Boosting the electrochemical performance of lithium-sulfur batteries by using a carbon black/LiMn2O4-modified separator

The large-scale applications of lithium-sulfur (Li–S) batteries have been limited by their rapid capacity loss, which can be attributed to the dissolution of polysulfide intermediates and subsequent irreversible shuttling effect. Several strategies have been attempted to solve these problems by designing novel cell structure, including the modification of separator. Herein, we have developed a new carbon black/LiMn2O4-modified separator for boosting the electrochemical performance of the Li–S batteries. The carbon black (Super P, for short SP) conductive layer plays the roles as an extra current collector for improving the utilization of active materials and a physical obstruction for restraining the diffusion of polysulfide intermediates. The LiMn2O4 (LMO) nanoparticles can chemically adsorb polysulfide intermediates and act as a fast channel for Li ions transportation. The as-prepared Li–S batteries with SP/LMO separators have delivered the discharge capacity of 1378.3 mAh g−1 for the initial cycle at 0.05C and 618.7 mAh g−1 after 300 cycles at 0.5C. The Li–S batteries also possess excellent rate performance and stability, retaining a discharge capacity of 427.1 mAh g−1 even under a high current density of 2 C. The Carbon black/LiMn2O4-modified separator was prepared by a facile blade-coating method. The carbon black (Super P) conductive layer plays the roles as an extra current collector for improving the utilization of active materials and a physical obstruction for restraining the diffusion of polysulfide intermediates. The LiMn2O4 nanoparticles not only have chemical binding with polysulfide intermediates, but also act as a fast channel for Li ions transportation. [Display omitted] •Carbon black/LiMn2O4-modified separator has been synthesized for Li–S battery.•LiMn2O4 has a strong adsorption capability for polysulfides and also promotes the fast transmission of Li ions.•The battery with high sulfur loading using the modified separator exhibited excellent electrochemical performance.