Hypercrosslinked Polymerization Enabled N-Doped Carbon Confined Fe2O3 Facilitating Li Polysulfides Interface Conversion for Li-S Batteries

Facilitating phase conversion efficiency of Li polysulfides to Li2S and restraining the dissolution of Li polysulfides are critical for stable lithium-sulfur (Li-S) batteries. Herein, an in situ formed sulfiphilic superfine Fe2O3 nanocrystals confined in lithiophilic N-doped microporous carbon (Fe2O3/N-MC) is derived from one-step hypercrosslinked polymerization. Uniquely, the dual active sites (Fe2O3 and N) in Fe2O3/N-MC tend to form "Fe-S, Li-O or Li-N" bonding, and then synchronically enhancing the chemisorption and interface conversion ability of Li polysulfides. As a result, 80 wt% S is loaded on Fe2O3/N-MC and the hybrid cathode delivers high mass capacity (730 mA h g(-1)) and excellent cycling stability (87.1% capacity retention over 1000 cycles at 5.0 C). Especially, the cathode also exhibits a high reversible areal capacity of 3.69 mA h cm(-2) at a high areal loading (5.1 mg cm(-2)) and a lean electrolyte/sulfur (E/S) ratio (7.5 mu L mg(-1)) over 500 cycles. This work is anticipated to deepen the comprehension of complex Li polysulfides interphase conversion processes and afford new thoughts for designing new host materials.