Preparation Of Ti₃C₂Tx MXene And Its Energy Storage Applications

MXene materials have been widely used in energy storage and conversion,environmental protection,medical treatment and many other fields due to their excellent properties of both metal and non-metallic materials.Among many MXene materials,it is one of the most widely studied and applied materials.In this paper,Ti₃AlC₂ was used as the precursor to prepare multilayer and single-layer Ti₃C₂Tx MXene materials by HF etching and LiF/HCl etching.The application of Ti₃C₂Tx MXene materials as supercapacitor materials was explored with 1mol/L H₂SO₄ as electrolyte.At the same time,in view of the low etching efficiency in the synthesis process of Ti₃C₂Tx MXene materials,ultrasonic technology was introduced into the etching process of Ti₃C₂Tx MXene materials,providing a new idea for the efficient synthesis of Ti₃C₂Tx MXene materials.The main research work of this paper can be summarized as follows:（1）The difference of the samples prepared from HF and LiF/HCl etching approaches were compared.SEM analysis results showed that Ti₃C₂Tx MXene materials prepared by HF etching method show typical"accordion"shape,while the samples prepared by LiF/HCl etching method show pleated structure;The results of X-ray diffraction analysis show that the Ti₃C₂Tx MXene material prepared by LiF/HCl etching method has larger layer spacing and better electrochemical performance than the Ti₃C₂Tx MXene material prepared by HF etching method due to the automatic insertion behavior of Li⁺in the etching process.（2）Ultrasonic technology is introduced into the etching process of Ti₃C₂Tx MXene materials prepared by HF etching method.The experimental results show that the ultrasonic assisted technology can effectively improve the etching efficiency of aluminum in the precursor.The residual rate of aluminum in the samples etched for 8 h under ultrasonic assistance is only 1.63 wt%,while the residual rate of aluminum in the samples without ultrasonic treatment at the same etching time is 7.88 wt%.The introduction of ultrasonic technology can effectively improve the electrochemical performance of the product.The specific capacitance of the sample prepared by ultrasonic for 8 hours is 155F/g,which is about 45 times that of the non-ultrasonic sample prepared under the same experimental conditions.（3）The ultrasonic technology was introduced into the etching process of Ti₃C₂Tx MXene materials prepared by LiF/HCl etching method.The experimental results show that the introduction of ultrasonic technology can effectively improve the specific surface area and electrochemical performance of the product.The specific surface area of the sample after ultrasonic assisted etching for 8 hours is 27.68 m²/g,which is much higher than that of the sample without ultrasonic treatment（3.29 m²/g）.In terms of electrochemical performance,the specific capacitance of the sample etched for 8 h with ultrasonic assistance is 270.5 F/g,which is 16 times higher than that of the sample etched without ultrasonic assistance.This is due to the insertion behavior of lithium ions promoted by ultrasonic.The specific capacitance of the single-layer MXene synthesized by ultrasonic assisted synthesis is 422.66 F/g,which is higher than that of the sample without ultrasonic treatment（280.5 F/g）.