Electrocatalytic polysulfide transformation for suppressing the shuttle effect of Li-S batteries

We report a method based on 2,4-dihydroxybenzoic acid-formaldehyde (RF-COOH) microsphere hard templates to prepare core-shelled Fe 2 O 3 microspheres , which were then added to graphene oxide to obtain hierarchical reduced graphene oxide, ultimately dropping Fe 2 O 3 (Fe 2 O 3 @rGO) by Vitamin C reduction and freeze drying. When used as cathode materials for lithium-sulfur batteries, Fe 2 O 3 @rGO shows a high specific capacity of 400.5 mAh g −1 at 2 C after 500 cycles. The prominent performance is due to the collaborative assembly of rGO , which provides stable   structural support and favourable conductivity, and core-shelled Fe 2 O 3 microspheres, which are certified to have a strong interaction with polysulfides. The   loose and stable skeletons of highly electroconductive rGO can offer a conductive framework for rapid ion/electron transport. Meanwhile, the unique core-shelled structure of Fe 2 O 3 with the ample void space can anchor polysulfides through the strong chemical adsorption and buffer the mechanical stresses caused by volume expansion during the charge and discharge processes. Moreover, Fe 2 O 3 promotes the transformation of polysulfides to insoluble LiPSs during the discharging process, effectively   alleviating the shuttling of the polysulfides.