Study On Preparation And Electrochemical Properties Of Cotinus Coggygria Flower-based Porous Biochar

As a modern electrical energy storage device,with its high power density and tens of thousands of times of charge and discharge cycle life,supercapacitors are increasingly used in new energy vehicles,solar photovoltaic power generation and wind power generation.Although some new carbon materials,such as graphene and carbon nanotubes,show superior electrochemical performance in supercapacitors,their high production cost and complex synthesis methods limit them to a large extent.Therefore,researchers have attracted researchers for their extensive resources,low prices,and environmentally friendly biomass materials.In this experiment,cotinus coggygria flower is used as a carbon source,and potassium hydroxide,lithium carbonate,and a complex of them are used as activators.Porous biochar is prepared by a high-temperature solid-phase method.Field emission electron microscope-energy dispersion spectrum?FESEM-EDS?,X-ray diffraction?XRD?and Raman spectrometer,specific surface area analyzer?BET?,and X-ray photoelectron spectrum?XPS?are utilized to characterize the sample.The electrode materials are assembled into supercapacitors to test their electrochemical performance.The experiment results indicate that with KOH as the activator,the total specific surface area of the obtained cotinus coggygria flower biochar material?KC-3-700?is1346.31 m² g^-1,when the mass ratio of PC carbon to KOH is 1:3 and the calcination temperature is 700°C,and the average pore size is 3.61 nm;the highest capacitances in 1M H₂SO₄ and 6 M KOH electrolytes are 348 F g^-11 and 229 F g^-1,respectively.With Li₂CO₃ as the activator,when the mass ratio of PC carbon to Li₂CO₃ is 1:3,the maximum capacitances of cotinus coggygria flower biochar material?LC-3?in 1 M H₂SO₄and 6 M KOH electrolytes are 218 F g^-11 and 239 F g^-1,separately.The composite activator is composed with different mixing ratio of KOH and Li₂CO₃.Under the optimal activation ratio?PC:composite activator=1:3?,when the ratio of Li₂CO₃to KOH is 1:1,the manufactured cotinus coggygria flower biochar material?C-2?delivers excellent specific capacitance of 413.5 F g^-11 in 1 M H₂SO₄ electrolyte and a high capacitance of 286 F g^-1 in 6 M KOH electrolyte,and after 36,000 cycles at a current density 5 A g^-1,the specific capacitance does not decrease.