Holey Reduced Graphene Oxide/rare Earth Oxide Modified Separator And Its Lithium-sulfur Battery Performance

Lithium-sulfur batteries are a promising candidate of next generation energy storage systems owing to its high theoretical capacity and energy density and abundant reserves and environmental friendliness of sulfur.However,the application of Li-S batteries still faces the intrinsic disadvantages:the soluble characteristics of the polysulfide intermediates(Li₂S_n,4?n?8)leads to irreversible capacity loss,shuttle effect and anode corrosion;the intrinsically poor electrical conductivities of sulfur and its discharge product(Li₂S/Li₂S₂)cause low sulfur utilization and slow reaction kinetics;uncontrollable Li dendrite growth gives rise to a short lifespan and catastrophic safety hazards.The modification of separator membranes is a simple and effective approach and has been widely used in recent years.In this paper,the holey reduced graphene oxide/rare earth oxide composites(hrGO-REO)are obtained through a simple preparation process and applied to the modification of the separator membranes.Effects of the reduced graphene oxide/rare earth oxide(rGO-REO)composites with holey on the electrochemical performance of lithium-sulfur batteries were experimentally studied.The results show that the hrGO-Nd₂O₃/PP modified separator displays better surface wettabillity and thermal stability.The cells with hrGO-Nd₂O₃/PP modified separator exhibit excellent cycling performance(the degradation is only 0.428%and the capacity remains at 328 m Ah/g after 154 cycles at 2 C)and excellent rate performance(high specific capacity of 963 m Ah/g at 0.1 C).The diffusion experimental results shows that the separator has a blocking effect on the diffusion of polysulfides.Influences of the modified separator with different rare earth oxides on the electrochemical performance of lithium-sulfur batteries were experimentally studied.The results show that the hrGO-La₂O₃/PP and hrGO-Ce₂O₃/PP modified separators also display excellent surface wettabillity and thermal stability.The cells with hrGO-Ce₂O₃/PP modified separator exhibit the best rate performance(the capacity remains at 588.3 m Ah/g after 200 cycles at 2 C)and excellent rate performance(high specific capacity of 1148.8m Ah/g at 0.1 C).This idea of constructing hrGO/REO modified separators provides a new strategy for the study of lithium-sulfur battery.