| Graphene has attracted tremendous attention for a wide range of applications in physics,chemistry and biology and showed a promising prospect.As like other allotropes of carbon,grphene has achieved the greatest performance in mechanical,electronics and thermal conductivity properties so far.Graphene has been applied to micro-electronics,information materials,bio-medicine,aerospace and energy storage based on its novel properties.But all the results still stay in laboratory-scale studies and few can be expanded to industry applications or achieve any profits.However,the thinner the graphene,the better the performance,but the higher the expense.Thus,we focused on the producing methods and the electrochemical performance of related products,trying to develop a new method with low cost and higher electrochemical performance that have access to the industry production.Also,optimum proposals corresponding to different applications of supercapacitor have been developed based on the deep research of its chemical mechanism.1.We put forward the pyrolysis of phthalocyanine for fabricating graphene products.All the experiments are carried out under Ar or N2 atmosphere.Firstly,the pyrolysis temperature of the procedure is investigated by comparing the products.800℃is proved to be the most befitting temperature for the pyrolysis reaction.The dehydrogenation and denitrogenation processes occur during the pyrolysis process and the organic macromolecules are transformed into an N-doped graphene layer.Besides,pyridinic N and pyrrole N are two main existential forms of N atoms in the graphene.Secondly,the reaction environment is investigated via a molten-salt system.Potassium chloride（KCl）,as the salt used,plays a key role in promoting the successful synthesis of the corrugated sheets,allowing the growth of phthalocyanine to form the herringbone-type molecular arrangement.A regular corrugation of5 nm is observed on the surface of the products.Besides,molten sodium chloride（NaCl）system have also been studied then and the corrugation becomes irregular.Importantly,they have proved that the molten salts have positive effect on prevent the stacking of the layers.2.Based on our previous knowledge on pyrolysis of Pc,more details about Pc-assisted fabrication of three-dimensional graphene have been discussed.The Van der vaals force andπ-πinteraction drive the GO and Pc to form a sandwiched composites and prevent their stacking.After the thermal treatment,both GO and Pc are reduced,hydrogen,water and carbon oxide molecule are released from the interlayer and a porous structure is therefore formed.For a better understanding of their evolution behavior,other derivatives of Pc have also been investigated.The insoluble Pc shows similar behavior when they interact with GO,a honeycomb-like three-dimensional graphene nanostructure is formed and not subject to the corresponding center metal atom.When metal-free Pc is applied as the precursor,the supercapacitor based on the PcG11 presents outstanding specific capacitance(175 F·g-1 at 0.5 A·g-1)even after 5000cycles.And for the soluble NiPcTs,the pyrolysis of sandwiched NiPcTs/GO composites forms a corrugated three-dimensional graphene nanoplate.Under three-electrode system,the NiPcTsG11 electrode shows the best performance of about 225 F·g-1 at current density of 0.5 A·g-1.3.A facile electrochemical method is carried out to produce bulk of graphene and the ammonium persulfate（APS）aqueous solution is applied as the electrolyte.Under the detailed investigation of different terminal voltage and intercalation mechanism,graphene powder,graphene fiber and thin graphene-based electrode paper have been produced according to different application requirements in energy storage devices.In conclusion,the best performed graphene fiber is achieved by exfoliating the graphite fiber at 2.5 V for 90mins,the capacity of the assembled EDLC reachs 70.6 mF·cm-2 at the current density of 0.3 mA·cm-2.Besides,a ultrathin（PVA/H3PO4）/graphene/graphite electrode paper is fabricated by a novel solid state electrolyte infusion technique.The thin paper-like electrode is thinner than 100μm and exhibits a sandwich hierarchical structure consisting of electrolyte（PVA/H3PO4）/graphene/graphite.This hierarchically structured paper-like electrode can be directly cut into arbitrary shapes or sizes in accordance with specific requirements.For example,the paper-like electrodes are tailored to be less than 500μm in width for further miniaturization.The assembled flexible,all-solid-state micro-supercapacitor devices exhibit excellent performance,such as a high volumetric capacitance of～3.6 F·cm-3 even after 20000 cycles.Notably,the devices also show excellent rate performance with extremely high specific capacitance retention of up to 94%as the current density is increased from 0.5 to 5A·cm-3,indicate their promising application in energy storage devices. |
