Preparation And Study Of Electrochemical Performance For Titanium Carbide Based Sulfur Cathode Composites

Due to the high energy density,environmental friendship and low production cost,Lithium sulfur batteries is considered to be one of the most developed battery systems.But the poor conductivity,the volume change in the charging and discharging process and the shuttle effect of the positive electrode,the development of lithium sulfur batteries has been seriously constrained.This topic is based on the catalytic effect of the two-dimensional transition metal carbide or nitride(MXene)material,iron-based oxide,and iron-based sulfide for polysulfide lithium,MXene composite is prepared by in situ growth and ultrasonic.The composite of Titanium(Ti₃C₂)and iron-based oxides and sulfides effectively inhibits shuttle effects for the lithium sulfur battery,the utilization of active materials is enhanced,capacity between Charge-discharge is increased,cycle performance and rate performance is improved.The results of this paper have certain reference significance for the design of high performance lithium-sulfur batteries.The Alk-Ti₃C₂ material of the three-dimensional pleat structure was obtained,and Alk-Ti₃C₂ was used to be a base material and additive for sulfur positive electrode.Relative to Ti₃C₂ material,sulfur be dispersed well in the Alk-Ti₃C₂and volume change is eased.In addition,the availability of active substances is improved due to better adsorption of polysulfides for Alk-Ti₃C₂.For substrate is used to loaded sulfur,the reversible specific capacity of Alk-Ti₃C₂/S is 263 m Ah g^-1 after 200 cycles,which is superior than Ti₃C₂/S.For the additive of CNT/S,the reversible specific capacity of Alk-Ti₃C₂ is 622 m Ah g^-1 after 100 cycles,which is superior than 472 m Ah g^-1 of the SP.On the basis of alkaline treatment of Ti₃C₂,iron oxides and iron sulfides were modified on three-dimensional folded Alk-Ti₃C₂ nanosheets,which are used as substrate to loaded sulfur and sulfur electrode additive.For the substrate to loaded sulfur,Alk-Ti₃C₂/Fe₃O₄/S-2.5 is prepared by in-situ growth,the capacity of which is 511 m Ah g^-1after 200 cycles and is superior than 100 m Ah g^-1 of the Alk-Ti₃C₂/S.Additives are studied,Alk-Ti₃C₂/Fe₃O₄-1.5 by in-situ growth and Alk-Ti₃C₂@Fe₃O₄-50 by ultrasonic play a important role in positive electrode,and Alk-Ti₃C₂@Fe₃O₄-50 has better performance,the reversible specific capacity of which is 717 m Ah g^-1 after 100 cycles.Alk-Ti₃C₂@Fe S₂also plays a similar role in the battery reaction.