Preparation Of Ti₃C₂T_x/Tungsten Materials Composite Electrode And Its Electrochemical Performance

In today’s society,energy storage equipment is very important for human production and life.Among all types of energy storage devices,supercapacitors have attracted a large number of researchers to explore and study them in different aspects due to their advantages such as high energy density,long cycle life and short time required in charge and discharge process,aiming at developing supercapacitors with more excellent performance.In order to achieve this goal as soon as possible,the researchers choose from the electrode material selection,design and other aspects of research.In recent years,a new type of MXenes material has been widely concerned by researchers because of its characteristic electrochemical properties when used as electrode materials.Among them,Ti₃C₂T_x material,a typical nanomaterial in MXenes family,has been studied in a variety of supercapacitors with different electrolytes due to its rich surface functional groups and good electrical conductivity.Especially when the electrolyte is H₂SO₄,the material is easier to show its own advantages,so as to improve its electrochemical energy storage performance.However,it is a pity that the material is easy to cause stacking between nanosheets under the action of van der Waals force,resulting in a decline in electrochemical performance.In order to effectively inhibit the stacking of the material nanosheets,1T-WS₂ nanosheets and W₁₈O₄₉ nanowires were selected as"spacers"to regulate the structure of Ti₃C₂T_x material.The two kinds of materials were respectively combined with Ti₃C₂T_x material,and the obtained composite materials can make the contact area between Ti₃C₂T_x material and electrolyte larger,and thus improve the electrochemical energy storage performance of the electrode material.The details are as follows:1T-WS₂/Ti₃C₂T_x nanocomposite are synthesized by hydrothermal method.The composite can not only effectively suppress the stacking problem of Ti₃C₂T_x material,but also improve the conductivity of 1T-WS₂ nanosheet electrode material.The growth of 1T-WS₂ nanosheets on Ti₃C₂T_x nanomaterial was observed by SEM and TEM characterization techniques.The electrochemical performance of the composites is tested.The results show that the specific capacitance of the composites reaches 333 F g^-1 at the scanning rate of 1 m V s^-1,which is higher than the specific capacitance of pure Ti₃C₂T_xand much higher than that of 1T-WS₂.Using 1T-WS₂/Ti₃C₂T_x nanocomposite as the negative electrode,the asymmetric supercapacitor has the highest energy density of 18.5Wh kg^-1.Two of these devices are connected in series to successfully power commercial red and yellow light emitting diodes（LEDs）.W₁₈O₄₉/Ti₃C₂T_x nanocomposite were synthesized for the first time by hydrothermal method and freeze-drying technology.The results showed that although the composite was synthesized by hydrothermal reaction at 200℃,no oxidation occurred in the Ti₃C₂T_xnanomaterial,which also provided a basis for the high and excellent properties of the composite.Specifically,when the electrolyte is 1 mol L^-1 H₂SO₄,the scanning rate of the material is 1 m V s^-1,and the specific capacitance can reach 472.6 F g^-1.When the scanning rate is increased by 100 times,the specific capacitance can still reach 346.4 F g^-1,and the capacitor retention rate is 73.3%,which has excellent magnification performance.With W₁₈O₄₉/Ti₃C₂T_x composite as the negative electrode and Ru O₂/CC as the positive electrode,the asymmetric supercapacitor assembled has an energy density of 27.66 Wh kg^-1 when the power density is 0.75 k W kg^-1.Two of the ASC devices are connected in series and,when fully charged,power commercial red LED.It shows that the material has a very wide application prospect.