Study On Electrical Performance Of Nitrogen-containing Composite Electrode Material Based On Disused Composite Panels

Supercapacitors are one kind of electrochemical energy storage devices with a high specific power density, which are promising in many energy-related applications, and currently can fill the gap between batteries and traditional capacitors. Activated carbons are the vital electrode materials that have been commercialized for the supercapacitors. In the development of supercapacitor, a proper control over the specific surface area and surface chemical of activated carbons are crucial to ensure a good performance of the supercapacitor. For the purpose of developed high performance supercapacitor electrode, we studied the preparation and modification technology of high performance carbon electrode material based on disused composite panels in this paper. The relevance between the characteristic of samples and the electrochemical performance of electrodes was discussed deeply.A series of nitrogen-containing activated carbon were prepared at different activation temperature and activator mass, from disused composite panels, using KOH as activating agent. In particular, the nitrogen-containing activated carbon prepared with a moderate KOFI/carbonization weight ratio of 3 at 800℃, which possesses a balanced specific surface area (1204 m2/g) and nitrogen content (2.07 wt.%) exhibits the largest specific capacitance of 181 F/g at a current density of 0.05 A/g, attributed to the co-contribution of double-layer capacitance and pseudo-capacitance.Besides, oxygen-and nitrogen-co-doped activated carbons were obtained from phosphoric acid treated nitrogen-doped activated carbons based on disused composite panels above-mentioned. The sample treated by 4 M H3PO4 of the highest capacitance (235 F/g) was measured in spite of a relatively lower surface (1360 m2/g) than that of the sample treated by 2 M H3PO4 (1433 m2/g). As the surface chemistry, and especially oxygen-and nitrogen-containing functional groups, was paramount importance for the capacitive behavior and for the effective pore space utilization by the electrolyte ions.Lastly, the porous graphene-activated carbon composites were prepared from pyrolyzed the mixture of graphene oxide and carbonization with the KOH as activator at 800 ℃. The weight ratio of graphene oxide and carbonization, as well as the dosage of KOH are all affect the characteristic and the electrochemical performance of the composites. The result show that the composite prepared with a carbonization and graphene oxide weight ratio of 4 and a KOH and carbonization plus graphene oxide weight ratio of 4, which possesses the best electrochemical performance. And the symmetric supercapacitor based on this sample offers a specific capacitance of 213 F/g at a current density of 0.05 A/g use 7 M KOH.