Design Of Electrode Materials For High Power Carbon-based Supercapacitors And Research On Energy Storage Performance

In recent years,China has put forward the work goal of"carbon peak,carbon neutral",due to the increasingly prominent contradiction between man and nature.which will set off a new round of innovation and development opportunities in the energy field.In all the energy storage equipment,supercapacitor with its series of advantages become a new star in the field of energy storage.However,due to the high cost and low energy density of carbon-based supercapacitors,their further wide application is limited.Based on this,this article focuses on the research and preparation of cheap and high energy density electrode materials.The main research contents and results are as follows:1.Using vinasse as raw material,a series of vinasse based porous carbon materials were prepared by carbonization and KOH activation.The porous carbon material JKPC-4-700 has a hierarchically distributed pore structure,and its specific surface area is as high as 3207 m² g^-1.In the solution of 6M KOH,the specific capacitance of JKPC-4-700 electrode is 517 F g^-1 at the current density of 1 A g^-1.When JKPC-4-700 is assembled into a symmetrical supercapacitor in EMIMBF₄ and the specific capacitance was up to 257 F g^-1(at 1 A g^-1).When the power density is 450 W kg^-1,the energy density can reach up to 144 Wh kg^-1.And the mass load of the active substance was?10 mg cm^-2,the specific capacitance retention rate can reach more than 73%,which is better than most porous carbon materials reported so far.2.Using the prepared vinasse porous carbon as a base material,a series of nanocomposite materials were prepared by a simple one-step hydrothermal method under a mild condition of 100°C.When Ni:Co=2:1,the product NiCo-LDH/JKPC-2composite material has a unique sea urchin-like structure.This structure provides a high specific surface area and abundant active site,improves electron transfer rate,enhances interfacial charge transport,shortening ion diffusion path,and the carbon material used also improves electrical conductivity and stability.At the current density is 1 A g^-1,the NiCo-LDH/JKPC-2 specific capacitance reaches 1454 F g^-1.When assembled into an asymmetric supercapacitor,the energy density reached 40.86 Wh kg^-1 at a power density of 775 W kg^-1.3.Tofu was selected as the raw material to prepare a series of porous carbon materials rich in heteroatoms through aging,fermentation,activation,and carbonization.The effects of activator ratio and activation temperature on various aspects of materials were investigated.The test found that the material GFPC-2-700 has a specific surface area as high as 3080.2 m² g^-1 and presents a three-dimensional hierarchical structure.In6M KOH solution,the specific capacitance is as high as 448 F g^-1 when the current density is 1 A g^-1.The corresponding symmetrical capacitor at 0.5 A g^-1 was tested in EMIMBF₄ and showed a specific capacitance of 332 F g^-1.At a power density of 450W kg^-1,it provides an energy density of up to 107.9Wh kg^-1.