Synthesis Of Ruthenium Oxide/Graphene Nanocomposite And Research On Supercapacitor Performance

Ruthenium oxide?RuO₂?has the advantage of high energy density as an electrode material for supercapacitors,but it is prone to agglomerate during the synthesis process,which results in a significant reduction of the active sites of the redox reaction.Graphene has a unique honeycomb arrangement of carbon atoms,with a theoretical area of up to 2630 m²/g.It is not only an excellent electrode material,but also suitable as a carrier,which can improve the phenomenon of RuO₂ agglomeration.However,due to the stacking problem of graphene,spacers are particularly important in RuO₂/graphene composite systems.Carbon nanotubes?CNTs?have a large specific surface area and good conductivity as spacers,which can greatly improve the performance of the composite.RuO₂/CNTs/Graphene ternary composites are currently ideal supercapacitor electrode materials.In addition,the problem of RuO₂agglomeration can be solved by reducing the growth time of RuO₂ particles.The microwave hydrothermal method can greatly shorten the experimental process,control the reaction time within minutes,and easily generate fine and uniform RuO₂particles.?1?Graphene oxide?GO?was prepared by an improved Hummers method,and single-walled carbon tubes?SWCNT?was introduced as spacers during the GO reduction process to form an S/G composite material.A ternary nanocomposite RuO₂@SWCNT/Graphene?RuO₂@S/G?was made by anchoring hydrous RuO₂nanoparticles to the surface of the S/G composite.The RuO₂@S/G electrode has a high specific capacitance of 988 F/g at a current density of 1 A/g and excellent rate performance,while the RuO₂@G electrode has a specific capacitance of only 640 F/g.Comparing with graphene,the results show that S/G is more suitable as a carbon skeleton for hydrous RuO₂ and can help RuO₂ nanoparticles to disperse.?2?RuO₂/SWCNT/Graphene?H-RSG?nanostructured electrode material was synthesized by a one-step hydrothermal method.In the hydrothermal process,RuO₂and SWCNT were selected as spacers to obtain less stacked graphene,and RuO₂nanoparticles were evenly anchored on the surface of graphene and SWCNT.The obtained H-RSG electrode material shows a high specific capacitance of 971 F/g at a current density of 1 A/g.When the current density is increased from 1 A/g to 10 A/g,the capacitance retention rate is 88%.That indicates the one-step hydrothermal method is not only as effective as sol-gel,but also the experimental method is simpler.More importantly,the one-step hydrothermal method realizes the simultaneous completion of the oxidation of ruthenium precursor and the reduction of graphene oxide,making the combination of the two closer and the rate performance better.?3?A ruthenium oxide/graphene composite?Microwave RuO₂/Graphene,MWRG?was synthesized by a microwave method.With the uniformity and speed of the microwave hydrothermal process,ultrafine RuO₂ nanoparticles were uniformly anchored on the two-dimensional graphene sheet.The obtained MWGR supercapacitor exhibits excellent electrochemical capacitance performance in H₂SO₄electrolyte with a specific capacitance of 845 F/g at a current density of 0.5 A/g and excellent cycle stability?capacitance retention is 92%after 10,000 cycles?.By increasing the current density,the supercapacitor was tested to have high rate performance and the capacitance retention rate is 95%.