Synthesis And Electrochemical Performance Of Holey Graphene/Polyaniline Composites

Supercapacitors are efficient electrochemical energy storage device s and have become one of the most studied energy storage devices,which is high power density,good cycle stability,fast charging speed,and environmental friendliness.Electrode material is the key factor determining the performance of supercapacitors.Among the many electrode materials of supercapacitors,holey graphene/polyaniline(HG/PANI)composite is a promising electrode material for supercapacitor due to its advantages of both conductive polymer and carbon-based material.In this study aims to further improve the electrochemical performance of PANI and HG by chemical modification.Firstly,HG/PANI composites were prepared by HG as the matrix.Subsequently,the holey graphene/sulfonated polyaniline(HG/SPANI)and functionalized holey graphene/Polyaniline(HG-PPD/PANI)composite were prepared by introducing sulfonic acid groups into the PANI molecular chain and functionalizing HG with p-phenylenediamine(PPD),respectively.The specific research contents and results are as follows:(1)GO as the raw material,hydrogen peroxide(H₂O₂)as etchant and Fe³⁺as catalyst for excessive H₂O₂ decomposition,aniline(An)was introduced into Fe³⁺environment to prepare HG/PANI composite.The mass ratio of An to HGO and the molar ratio of An to Fe³⁺were investigated for the electrochemical properties of the HG/PANI composite.The results show that when the mass ratio of An to HGO is 30:1 and the molar ratio of Fe³⁺to An is 0.5:1,the HG/PANI composite has a regular lamellar structure and has the best electrochemical performance.The specific capacitance of HG/PANI composite is 627.2 F g^-1 at the current density of 0.5 A g^-1.The specific capacitance retention rate of the composites is 90.5%after 2000 cycle stability tests.(2)GO as the raw material,H₂O₂ is an etchant,Fe³⁺is an excess of H₂O₂decomposition catalyst,the An and orthanilic acid(OA)were introduced into the environment of Fe³⁺to prepare the HG/SPANI composite material.The effects of the molar ratio of An and OA electrochemical properties of HG/SPANI composites were investigated.The results show that when the molar ratio of An to OA is 9:1,SPANI nanoparticles were uniformly grown on the surface of the HG sheets,and the HG/SPANI composites with optimal electrochemical properties were prepared.The HG/SPANI composite has a specific capacitance of 631.7 F g^-1 at a current density of0.5 A g^-1,the current density increased from 0.5 A g^-1 to 20 A g^-1,the capacitance retention rate was as high as 80.0%.After 2000 cycle stability tests,the capacitance retention rate was 86.6%.(3)Functionalized holey graphene materials(HG-PPD)were prepared by using GO as raw material,H₂O₂ as etching agent,PPD as reductant and functionalized material.Then,the An monomer was added to the HG-PPD solution and the HG-PPD/PANI composite was prepared by in-situ polymerization.The effects of the mass of PPD and HGO on the electrochemical properties of HG-PPD and the effect of the mass ratio of An to HGO on the electrochemical properties of HG-PPD/PANI composites were investigated.The results show that when the mass ratio of PPD to HGO is 2:1,the HG-PPD material has a porous structure.It has the highest specific capacitance of 426.7 F g^-1(0.5 A g^-1).After 2000 cycle stability tests,the capacitance retention rate is 97.2%.When the mass ratio of An to HGO is 10:1,the granular PANI in HG-PPD/PANI composite grows uniformly on the surface of HG-PPD sheets,and the fibrous PANI connects different HG-PPD sheets.The specific capacitance of HG-PPD/PANI composite is 568.9 F g^-1 at a current density of 0.5 A g^-1.After 2000cycles stability test,the specific capacitance retention rate is 87.4%.