Effect Of CeO₂ Based Composite Cathode Materials On Electrochemical Performance Of Li-S Batteries

Excessive exploitation and utilization of fossil energy has exerted a great impact on human's living environment,but human's demand for energy is growing.Although lithium-ion batteries have made significant progress,they still face the challenges of poor cycle stability and low energy density in practical use.Because of its high energy density(2600 Wh·kg^-1)and capacity density(1675 m Ah·g^-1),lithium-sulfur battery is considered as the next most promising secondary battery.However,the poor conductivity and the"shuttle effect"in the reaction process become the obstacles of the lithium sulfur battery.In this paper,by preparing CeO₂/GR(cerium oxide/graphene composite)interlayer,the effect of CeO₂ addition amount on the properties of CeO₂/GR/CNTs(carbon nanotubes)/S composites were studied.On this basis,the influence of the thickness of CeO₂/GR interlayer on the electrical properties of the composite was also studied.Prepared CeO₂@CNTs composite.The effect of CeO₂ content on the properties of composite was studied CeO₂@CNTs/S On this basis,the effect of annealing temperature on the electrical properties of the composite cathode materials was studied CeO₂@CNTs/S.Effect of composite materials on the electrical properties of cathode.The specific results are as follows:(1)Adopting secondary coating prepared the CeO₂/GR interlayer,after the positive on CNTs/S interlayer,the positive electrical conductivity improved significantly,at the same time,the intercalation of CeO₂ in the cell reaction process since it has the oxygen vacancy easy adsorption polysulfide ions,so the battery discharge specific capacity and cyclic stability performance synchronous improved,manifests the interlining for effective inhibition of"shuttle effect".When the dosage of CeO₂ is 1.8 wt.%,the discharge specific capacity at 0.1 C is1486 m Ah·g^-1 for the first time,and remains 511.3 m Ah·g^-1 after 350 charge-discharge times(2)Based on the determination of the optimal amount of CeO₂ in the sandwich is 1.8 wt.%,the sandwich with different thickness is prepared by adjusting the thickness of the electric roller.It is found that when the interlayer thickness is 10?m,the specific discharge capacity of the battery is the highest,and the cycle is the most stable(3)CeO₂ doped CNTs composite were prepared by hydrothermal method.The 3D network structure can not only increase the conductivity of the material,but also adsorb polysulfide.It was found that when the dosage of CeO₂ is 3.5wt.%,the discharge specific capacity reaches 1437.6 m Ah g^-1 at 0.1C for the first time,and can still be maintained to 660.4 m Ah g^-1 after 300 times of charge and discharge(4)The CeO₂@CNTs with different annealing temperatures were prepared on the basis of the optimum addition of CeO₂ of 3.5 wt.%.It is found that CeO₂@CNTs/S composite has the best adsorption performance of polysulfide when the annealing temperature is 800?.