Synthesis And Electrochemical Performance Of MXene-based Composite With Superlarge Interlayer Spacing

As a newly emerging two-dimensional transition metal carbon/nitride,MXene,like graphene,has a significant two-dimensional structure.In addition to the properties of traditional two-dimensional materials,MXene is because of its excellent properties.Its electrical conductivity,good hydrophilicity and large volume specific capacity have attracted the attention and favor of researchers.However,the narrow MXene layer spacing and low specific capacity have seriously affected the performance of MXene in various fields,especially in the electrochemical field,and have also limited its application in electrochemical performance.LTO has outstanding cyclic stability,Li⁺has a good intercalation effect in the preparation and application of MXene;Na₂Ti₃O₇ has a high specific capacity,strong conductivity,and a strong alkaline solution can effectively modify the surface groups of MXene.Therefore,the use of NaOH MXene materials modified by strong bases such as Li⁺,make MXene materials into MXene-LTO,MXene-Na₂Ti₃O₇ and other MXene composites,thereby effectively expanding the layer spacing of MXene,greatly increasing the specific capacity of MXene,Therefore,this paper mainly studies the modification of MXene by expanding the distance between MXene layers and modifying MXene with a strong base.First,in order to improve the shortcomings of the narrow layer spacing of Ti₃C₂ nanomaterials,this article for the first time made LTO grow in situ in the interlayers of two-dimensional Ti₃C₂ nanomaterials.The pillar effect of LTO in two-dimensional Ti₃C₂ nanomaterials was significantly increased.The interlayer spacing of Ti₃C₂ increases the active sites of two-dimensional Ti₃C₂ materials.The Ti₃C₂/LTO composite is prepared by a simple,safe,and fast heating and stirring method.Studies have shown that this modification effectively enhances the two-dimensional Ti₃C₂ materials.Lithium storage capacity greatly increases the capacity of the material.In the voltage range of 0-2.5V?vs.Li⁺/Li?,Ti₃C₂/Li₄Ti₅O₁₂ has a reversible capacity of 265.2 mAhg^-1 at a rate of 0.5C,and even at a high rate of 30C,it still has 172.5 mAhg^-1 Reversible capacity.Ti₃C₂/Li₄Ti₅O₁₂ composite nanomaterial will have a great application prospect as a new metal carbide-based composite material to meet the requirements of high power,high scan speed,and ultra-long-term rate performance.In addition,we also successfully synthesized in situ grown MXene/Na₂Ti₃O₇ composites with a flower-like array structure in a strongly alkaline solution system using hydrothermal treatment methods.One sentence because of the large capacity of Na₂Ti₃O₇),MXene has more active sites for accommodating electron ions,so the material exhibits amazing electrochemical performance,in the voltage range of 0-2.5V?vs.Li⁺/Li?The Ti₃C₂/Na₂Ti₃O₇ nanocomposite has a huge reversible capacity of 225.2 mAhg^-1 at a rate of 0.5C,and still has a reversible capacity of 145.43 mAhg^-1 under high-rate conditions.From this we can conclude that Ti₃C₂/Na₂Ti₃O₇ composite materials will have a good application prospect in the new generation of lithium-ion batteries.