High-Performance Li-S Battery Cathode Enabled by Immobilizing Sulfur in Hybrid Janus Host with Hierarchical Structure

Abstract A facile and effective strategy is proposed to fabricate high-performance Li-S battery cathodes with a hierarchically structural Janus host composed of multiwall carbon nanotubes (MWCNTs) and polyethyleneimine (PEI). The MWCNTs act as conductive skeleton for physical confinement of S and the PEI can chemically immobilize the S/lithium polysulfides. Benefiting from synergistic effects of the multifunctional host, the cathode can load with high S and simultaneously achieves excellent reversible capacity and outstanding rate performance. For instance, the capacity remains around 500 mAh g −1 even after 350 cycles at 0.2 A g −1 with a capacity decay of only 0.12% per cycle. Even at a higher rate current of 1 A g −1 , the per cycle capacity decay is only 0.1% within 160 cycles.