Preparation And Study For Electrode Materials Of Flexible Polyaniline Supercapacitors

With the development of times,more and more smart devices are came out which always need the indispensable participation of flexible supercapacitors.The great challenge of fabricating flexible supercapacitors is to design and synthesize electrode materials which possess both excellent electrochemical(high capacity,good rate capability,long-cycling stability,high conductivity)and mechanical properties,and that is to say the electrochemical properties of the electrode materials should be well kept when faced with great deformation.In this paper,the flexible composite of reduced graphene oxide ribbon(RGO-ribbon)/polyaniline-polyvinyl alcohol(PRP)was prepared through the combination of in-situ polymerization and chemical reduction reaction based on the carbon matrix of graphene oxide ribbon(GO-ribbon)which has excellent conductivity and mechanical flexibility,the electrochemical active substance of polyaniline(PANI)and the flexibility unit of polyvinyl(PVA).The effects of synthesis process parameters towards the microstructure,electrochemical and mechanical properties of flexible composite were clearly investigated.Furthermore,the synthesis and energy storage mechanisms were also discussed.On this basis,the electrochemical stability of the all-solid flexible supercapacitors based on the gel electrolyte of H₂SO₄/polyvinyl under great deformation was particularly studied.The details are as follows:(1)The aniline can be easily deposited on the surface of carbon matrix of GO-ribbon based on the in situ polymerization.In the process,with the addition of3-amino-phenylboronic acid,the PVA and GO-ribbon/PANI can be crosslinked at the molecule level through the condensation of boronic acid and PVA.And then,the flexible electrode material of PRP was prepared after the chemical reduction by HI.In this paper,the effects of the synthesis process parameters(the morphology of graphene matrix,the contents of PANI and cross-linking agent)towards the microstructure and electrochemical property was detailly investigated.The research results indicated that the RGO-ribbon wrapped in the PANI can not only act as carbon support and conductive network,but also construct macro-porous structure through the cross-linking effect with PANI,benefiting for the fast transfer of electron and electrolyte ions within the electrode materials.Meanwhile,the flexible skeleton consisting of RGO-ribbon and PVA can also inhibit the destroying of conductive network form the repeated expansion and shrink during the continuous charge/discharge process.As a result,the prepared PRP electrode exhibits high capacity,excellent rate capability and good cycling stability in the application of all-solid flexible supercapacitors.(2)The mechanical properties of PRP were further investigated based on the electrochemical experiments.The research results indicated that the tensile strength(tensile break stress of 31 Pa,tensile break deformation of 77.25%)and compression strength(138Mpa,compressive deformation of 70%)were obviously enhanced based on the fabrication of elasticity network consisting of RGO-ribbon and PVA.Moreover,the all-solid flexible supercapacitor with sandwiched structure was fabricated,in which the PRP was used as flexible electrode materials and the H₂SO₄/PVA was used as gel electrolyte.The all-solid supercapacitor exhibits both excellent electrochemical and mechanical properties.After folding in 180° for 1000 times,the all-solid supercapacitor still exhibit high capacity retention as high as 93.97%...