Structural Design And Performance Reasearch Of Novel Supercapacitors Materials

Supercapacitor is one of the most important energy storage devices,but its limited energy density and traditional structure limit its application in more extensive and diversified fields.The "high-performance" and "multifunction"of supercapacitors are the development directions and hotspots in this research field,which have important theoretical significance and potential application value.In this thesis,high-performance and multifunction supercapacitors are constructed from two aspects:novel electrode materials for supercapacitors and the design and fabrication of the integrated device of multifunction supercapacitors.The main works of this thesis are as follows:1.A novel supercapacitor electrode material nickel cobalt telluride(Ni0.33Co0.67Te)with excellent electrochemical performance was designed and prepared:bimetallic nickel cobalt telluride with high conductivity is conducive to electron transmission and electrochemical reaction under high power.Nickel cobalt telluride is deposited on the nickel foam by a facile solvothermal and ion-exchange reaction.Ni0.33Co0.67Te nanotubes interpenetrate each other on the nickel foam skeleton to form a hierarchical pore structure.The diameter of Ni0.33Co0.67Te nanotubes are about 40 nm,the wall thickness is only 9 nm,and the length can reach tens of microns.The specific capacity of the prepared electrode reaches 131.2 mA h g-1 at 1 A g-1.Even the current increases 20 times,the specific capacity can still reach 79.3 mA h g-1.After assembling it as a positive electrode material and an active carbon negative electrode into a hybrid supercapacitor,it showed a energy density of 54.0 W h kg-1(918 W kg-1).The capacity retention rate can still reach 90%after 5000 charge-discharge cycles,indicating its excellent electrochemical performance.2.Based on polyacrylic acid(PAA)based hydrogel with double cross-linking enhanced network and excellent ionic conductivity,electrodes and polyelectrolytes with stretchable and self-healing performance were prepared by free radical polymerization.During the assembly process,electrode/electrolyte interface disappears due to the dynamic bonding of hydrogen bonds and ionic bonds,and finally an integrated device is obtained.The prepared PAA-based hydrogel showed a tensile strength of 31.7 kPa and a break strain of 967%.The ion conductivity of the hydrogel polyelectrolyte can reach 0.18 S cm-1.The area capacitance of the assembled device can reach 547 mF cm-2 at 0.5 mA cm-2;the energy density can reach 0.076 mW h cm-2,when the power density is 0.54 mW cm-2,indicating its good electrochemical performance.