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 Fe2O3 microspheres, which were then added to graphene oxide to obtain hierarchical reduced graphene oxide, ultimately dropping Fe2O3 (Fe2O3@rGO) by Vitamin C reduction and freeze drying. When used as cathode materials for lithium-sulfur batteries, Fe2O3@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 Fe2O3 microspheres, which are certified to have a strong interaction with polysulfides. The loose and stable skeletons of highly electroconductive rGO can offer a conducive framework for rapid ion/electron transport. Meanwhile, the unique core-shelled structure of Fe2O3 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, Fe2O3 promotes the transformation of polysulfides to insoluble LiPSs during the discharging process, effectively alleviating the shuttling of the polysulfides.