High sulfur-containing organosulfur polymer composite cathode embedded by monoclinic S for lithium sulfur batteries

Lithium sulfur (Li–S) battery is considered as one of the most viable candidates for next-generation rechargeable batteries. However, the development of Li–S battery is severely hindered by the stubborn "shuttle" issue that arises from the dissolution of the intermediate polysulfides. Herein, a new kind of organosulfur polymer composite is designed as cathode material for Li–S batteries. Via a facile two-step heating method, the ring opening S is copolymerized with triallyl isocyanurate. The resulting S-triallyl isocyanurate organosulfur polymer composite (STI) demonstrates a unique two-phase structure: ultrafine monoclinic S particles embedded in the organosulfur polymer matrix, which enables a S content as high as 90 ​wt%. The STI cathode delivers a high initial reversible capacity of 904 ​mA ​h ​g−1 at 0.5 ​C, and an ultraslow capacity decay rate of 0.017% over 350 cycles at 1 ​C. The work offers new insights into the design of S-rich copolymer composite cathode for highly-stable Li–S batteries.