The Construction Of Ti₃C₂ And Manganese Dioxide Hybrid Electrode For Electrochemical Application

Two-dimensional(2D)nanometer materials with high specific surface area and flexibility,are regarded as a promising building platform for flexible supercapacitors.In a large number of 2D nanomaterials,transition metal oxide(TMO)is widely known as the most representative pseudo-electrochemical active material.It is well known for its high theoretical capacitance,abundant nature and large energy density.Improving their structure and compounding with other conductive materials are common methods to improve the performance of 2D TMO capacitors at present.Unfortunately,most of the composite electrodes have an inhomogeneous mixture of active substances,which often results in greater internal resistance and poor stability,which ultimately limits the further improvement of the electrode capacitance.Therefore,it is still a great challenge to find a way to effectively enhance the capacitance of 2D TMO and apply them to flexible devices.In this study,we coupled MnO2 with a new 2D nanometer material Ti3C2 through an easy and adjustable mixing and filtration method.As a result,we got the MnO2/Ti3C2 hybrid electrode,and studied its relative electrochemical performance.The main contents of this work are as following:(1)The preparation of ultrathin MnO2 and Ti3C2 nanosheets and study on their electrochemical performanceHerein,we have got the MnO2 and Ti3C2 nanosheets solution through top-down stripping way.With the help of vacuum and pressing way,we prepared electrode materials,and made electrochemical test.In addition,because the Ti3C2 nanosheets used in this article is different from that of other published articles,the work further compared and explored the mechanism of Ti3C2 electrochemical performance.(2)Preparation and Study on the electrochemical performance of MnO2/Ti3C2 hybrid electrode materialsIn this study,we reported for the first time coupling MnO2 and Ti3C2 sheets for use as high-performance flexible film supercapacitors by taking advantage of their similar 2D geometry,their good compatibility,the high capacitance from MnO2,and the excellent conductivity of titanium carbides,which finally achieved the better performance.At first,the hybrid film of molecularly stacking the ingredient MnO2 and Ti3C2 sheets was produced by a simple strategy of filtering the dispersion after mixing the two solutions.Then,the electrochemical performance of the composite electrode was preliminarily explored through the three electrode test system.Under the three electrode test condition,the composite electrode has a high specific capacitance,and the corresponding capacitance value is 305 F g-1 when the current density is 1 A g-1.It was worth mentioning that after 6000 cycles,the electrode has a capacitance retention rate of up to 93%.Based on the performance of composite electrodes,we further constructed the symmetrical flexible supercapacitor devices,and achieved the best energy density of 8.3 Wh kg-1 and the highest power density 2376 W kg-1 in 1 M Na2SO4 aqueous solution.In addition,in order to further prove the advantages of our electrode structure,we also compared the electrochemical performance of MnO2-Ti3C2 composite electrode prepared by traditional method of electrode preparation with the MnO2/Ti3C2 composite electrode reported in this work,proving the electrode structure in this work is more beneficial to improve the electrochemical performance of the electrode.