Preparation And Performance Research Of Triphenylamine Based Covalent Organic Frameworks(COFs) Supercapacitor Electrode Materials

With the increasingly serious energy crisis,people have to find new renewable energy sources to replace fossil energy sources such as coal,oil,and natural gas.At present,as a relatively clean energy source,electric energy is used in various fields,but its energy conversion efficiency in the process of energy storage and release is low,resulting in a large amount of energy waste.Electrochemical energy storage(EES)equipment can convert electrical energy in the grid into stable chemical energy for storage,so that it can be converted back to electrical energy when needed.Supercapacitor is a new type of energy storage device between conventional batteries and traditional capacitors.It has the advantages of short charging time,high power density,and long cycle life.It has been used in solar energy systems and wind power generation systems.As well as new energy vehicles,which can meet most high-power applications,they have received extensive attention.The electrode materials of supercapacitors mainly include carbon materials,metal oxides and conductive polymers.Covalent Organic Frameworks(COFs),as a new type of porous material,have adjustable pore structure,diversified construction modules,and?-?stacking structure between layers can effectively promote electron conduction,and This porous regular structure can also promote ion transmission in the electrolyte,improve transmission efficiency,and has potential application value in electrochemical energy storage,which has attracted great attention from the scientific community.In this paper,solvothermal method is used,and Tris(4-aminophenyl)Amine(TAPA)and Tris(4-Formylphenylfr)Amine(TFPA)are used as the unit was constructed,and TPA-COFs materials were prepared.Observe the morphology and size of the sample by SEM and TEM,XRD,FT-IR,Raman and other methods to characterize the microstructure of the material.Thermogravimetry and nitrogen adsorption and desorption have an effect on the thermal stability,specific surface area and the hole structure are tested.Use CV,EIS,GCD and cycle stability tests to test the electrochemical performance of the materials.By studying the synthesis conditions of TPA-COFs,the best reaction temperature is 120?,and the reaction time is 3d.At this time,the TPA-COFs materials have a uniform nanorod structure,the best crystal form,and the highest specific capacitance.In order to compare the effects of different electrolytes on the electrochemical performance of COFs,the TPA-COFs prepared under the optimal conditions were tested in two different electrolytes:1M H₂SO₄ and 0.1M LiClO₄/acetonitrile.The results showed that when 1M H₂SO₄ was used as the electrolyte,its performance was better.The specific capacitance is 176.7Fg^-1 at 0.5Ag^-1 and 95.6Fg^-1 at 10Ag^-1,and the capacitance retention rate is 54.1%.The prepared TPA-COFs electrodes materials exhibit good cycle stability in aqueous electrolyte.After 10,000 cycles,the capacitance retention rate of the materials is 135%,and the coulombic efficiency is 108%.Polyaniline is one of the most promising electrode materials for pseudocapacitance applications due to its low cost,high conductivity in the doped form,rapid and stable transition between the doped state and the reduced state,and simple synthesis.In order to improve the conductivity of electrode materials,we combined COFs with conductive polyaniline.Using tris(4-aminophenyl)amine,tris(4-formylphenyl)amine and aniline as raw materials,the TPA-COFs/PANI composites electrode materials were prepared by two methods:electrodeposition and solvothermal.With the purpose of explore the influence of the order of adding PANI on the properties of the composites,the structure and morphology of the composites were characterized,and the capacitance performance was tested.The results found that the TPA-COFs/PANI-20composites materials synthesized by solvothermal method have the most excellent electrochemical performance.The specific capacitance can reach 333.06Fg^-1 at 0.5Ag^-1,and the specific capacitance can reach 246.96Fg^-1 at 10Ag^-1,its capacitance retention rate is74.15%.The prepared composites materials also exhibited excellent cycle stability after 10,000cycles,with a capacitance retention rate of 115% and a coulombic efficiency of 120%.In order to further evaluate the capacitance performance of composites materials in practical applications,TPA-COFs/PANI-20 and activated carbon(AC)are used as positive and negative materials to assemble TPA-COFs/PANI-20//AC-ASC asymmetric capacitors.Its energy density can reach 51Whkg^-1 at a power density of 267Wkg^-1.