Construction Of Activated Carbon Particle / Reduced Graphene Oxide Composite Electrode And Its Supercapacitor Performance

With the increasing demand of production and manufacturing industry and the increasing problems of ecological environment in modern society,more and more attention has been paid to the research of new,low-cost,environmental protection and high-performance energy storage system.Supercapacitors,also known as electrochemical capacitors,are considered to be a promising alternative to traditional energy storage equipment because of their high power,long cycle life,simple principle,high dynamic charge transfer and low maintenance cost.Supercapacitor is composed of electrode material,current collector,electrolyte and separator.Electrode material is the most important component of supercapacitor,which directly affects the physical,mechanical and electrochemical properties of supercapacitor devices.In this paper,the filter element of waste water purifier and graphene oxide are used as raw materials,and the activated carbon particles are uniformly attached to the surface of reduced graphene oxide.The influence of the ratio of activated carbon particles and reduced graphene oxide on the performance of supercapacitor is explored,and the sample with the best ratio was analyzed in depth.With the best sample as raw material,the mixed flexible film of activated carbon particles and reduced graphene oxide was prepared by a simple vacuum filtration method.The main research contents are as follows:1. Using the filter element of waste water purifier as the precursor of activated carbon,through a simple activation process,the activated carbon particles are uniformly attached to the surface of the reduced graphene oxide.In this unique structure,the reduced graphene oxide are beneficial for improving the electrochemical performance of the activated carbon particles,while activated carbon particles can effectively inhibit the re-stacking of the reduced graphene oxide sheets.Therefore,the symmetric supercapacitor based on this composite electrode?RGO-ACP3?delivers high specific capacitance of 116.88 F g^-1 at a current density of 0.5 A g^-1 in 1 M H₂SO₄ electrolyte,and has a high capacitance retention of 97.85%even after 8000 cycles at at a current density of 5A g^-1.More importantly,from the perspective of activated carbon particles,adding a portion of reduced graphene oxide to three portion of low-cost activated carbon can increase the specific capacitance of the electrode material by 58.2%.It also provides high energy density of 11.90 Wh kg^-1 at power density of 469.24 W kg^-1 in 1M Na₂SO₄ electrolyte.In addition,the normalized special capacitance contributed by reduced graphene oxide in the RGO-ACP15 reaches up to 541 F g^-1 at 0.5 A g^-1 in 1 M H₂SO₄.The results indicate that the synergistic effect between reduced graphene oxide sheets and activated carbon particles makes RGO-ACP3 a promising low cost electrode material for high performance supercapacitors.2. Activated carbon particles and reduced graphene oxide were mixed into a uniform suspension at a ratio of 1:3,and the uniformly mixed dispersion was vacuum filtered using Celgard2500 membrane.Activated carbon particles and reduced graphene oxide are further cross-linked,and the flexible film with certain strength and flexibility is obtained.The film has a high area capacitance of 120.3 m F cm^-2 at a current of 1m A.And the film has good flexibility,even in the bending state of 0-180 degrees can still maintain good electrochemical performance.