Conducting Polymers Crosslinked with Sulfur as Cathode Materials for High‐Rate, Ultralong‐Life Lithium–Sulfur Batteries

Low electrical conductivity and a lack of chemical confinement are two major factors that limit the rate performances and cycling stabilities of cathode materials in lithium–sulfur (Li−S) batteries. Herein, sulfur is copolymerized with poly( m ‐aminothiophenol) (PMAT) nanoplates through inverse vulcanization to form the highly crosslinked copolymer cp(S‐PMAT) in which approximately 80 wt % of the feed sulfur is bonded chemically to the thiol groups of PMAT. A cp(S‐PMAT)/C‐based cathode exhibits a high discharge capacity of 1240 mAh g −1 at 0.1 C and remarkable rate capacities of 880 mAh g −1 at 1 C and 600 mAh g −1 at 5 C. Moreover, it can retain a capacity of 495 mAh g −1 after 1000 deep discharge–charge cycles at 2 C; this corresponds to a retention of 66.9 % and a decay rate of only 0.040 % per cycle. Such a remarkable rate performance is attributed to the highly conductive pathways of PMAT nanoplates, and the excellent cycling stability is ascribed mainly to the chemical confinement of sulfur through a large number of stable covalent bonds between sulfur and the thiol groups of PMAT. The results suggest that this strategy is a viable paradigm for the design and engineering of conducting polymers with reactive functional groups as effective electrode materials for high‐performance Li−S batteries.