Capacitor Storage Performance Of Covalent Organic Polymers With Anthraquinone And Pyridine Nitrogen Groups And Their Derivatives

Covalent organic polymers(COPs)with special characteristics of low mass density,good crystallinity,excellent chemical stability,and high surface area have been widely applied in the fields..such as gas storage,separation,heterogeneous catalysis,and energy storage.Recent studies have found that covalent organic polymer materials can be used as pseudocapacitance storage materials with anthraquinone groups and pyridine N blocks as tunable redox-active functionalitiesin in acidic media.This type of polymer is difficult to be electrochemically accessible,owing to the undesirable nonconductive nature of COPs and easily buried characteristics of the redox-active moieties in the randomly oriented COP layers.Moreover,polymers are easily degraded in alkaline electrolyte,which makes it difficult to realize effective storage of the capacitors.In this paper,the new type of covalent organic polymer is compounded on the functionalized carrier composed of graphene oxide in order to prepare three composite materials with good capacitance storage properties in both alkaline and acidic media.The main research contents are as follows:(1)amine group-functionalized graphene as the carrier,1,4,5,8tetra-minoanthraquinone with redox activity is selected as the energy storage component of COPs.Terephthalaldehyde or 2,6-pyridinedicarbaldehyde are choosed as the connecting units to constructed two types of four-arm covalent organic polymer composite FTAPA@NH₂-rGO and FTAPD@NH₂-rGO materials.Both types of materials have rich mesoporous structure and lamellar morphology.Among them,the FTAPA@NH₂-rGO composite material shows excellent capacitor storage performance in both acidic and alkaline solutions.The maximum specific capacitance in 2.0 M H₂SO₄ is 310 F g^-1,which is much higher than pure FTAPA covalent organic polymer and amine graphene.And it also has a specific capacitance of 400 F g^-1 in 6.0M KOH alkaline medium.The cyclic charge-discharge test within 2000 cycles at a current density of 5 A g^-1 confirmed that the composite material maintained good capacitance storage stability in both media.(2)amine group-functionalized graphene as the carrier,selecting1,4-diaminoanthraquinone with redox activity as the energy storage component of COPs,1,3,5-Tris(4-formylphenyl)benzene and 2,4,6-triformylphloroglucinol as the connecting unit,two types of lamellar covalent organic polymer composite graphene material are constructed.The synthesized TPDA@NH₂-rGO material owes a specific surface area of 122.2 m² g^-1.It not only has a maximum specific capacitance of 390 F g^-1 in 2.0 M H₂SO₄ electrolyte,which is better than most covalent organic polymer materials reported in the literature,but also has a maximum specific capacitance of522 F g^-1 at 6.0 M KOH solution.Under the current density of 5 A g^-1 within 2000cycles the storage performance of capacitor maintains good stability.(3)graphene and multi-walled carbon nanotube mixture as the functionalized carrier,3,3-diaminobenzidine was selected as the energy storage component of COPs,2,6-pyridinedicarbaldehyde as the connecting unit,and chlorinated with tetrahydrate Manganese is used as the metal source to synthesize a new type of graphene and carbon nanotube-supported salen-type covalent polymer.The Mn-COPs/C composite material also has a certain capacity storage performance.Through further pyrolysis,MnOx@NC-800 with rich mesoporous structure was obtained.The capacitive storage performance of pyrolysis-derived carbon materials has been significantly improved.The specific capacitance can reach 408 F g^-1 in 6.0 M KOH alkaline electrolyte,and it can reach 310 F g^-1under the acidic condition of 2.0 M H₂SO₄,which is stable within2000 cycles in both media.