| With the advancement of technology and the popularization of electronic products,the demand for energy storage equipment is increasing.Search for energy storage devices with higher capacity,faster charge/discharge speed and higher density are the important direction of electrochemical development.Supercapacitor（SC）is an energy storage device different from convention capacitors and secondary batteries.It has the advantages of high capacitance,high power density,fast charging and discharging speed,ultra-long cycle life,wide working temperature range and green safety,and has attracted researchers’attention.However,the low energy density limits the practical application of supercapacitors.The electrode material is one of the core components of supercapacitors,which has important influences on its electrochemical performance.Generally,electrode materials mainly store electrical energy by generating electric double layers and accumulating charge,so it is required that electrode materials should have large specific surface area and great electrical conductivity.Carbon is the most common electrode material for electric double layer supercapacitors.The current preparation of carbon materials is mainly based on non-renewable energy sources such as carbon-containing products and waste materials produced during the refining process of coal and petroleum.In order to realize the vision of sustainable development,the use of biomass as a raw material to prepare porous carbon is a quite promising approach.Biomass is a kind of clean energy with high yield,low cost,wide distribution and high carbon content,which is very suitable for preparation of carbon materials.Yet for carbon as the electrode materials,obtaining a larger specific surface area and an appropriate pore size distribution is a huge challenge in practical applications.Therefore,exploring simple and efficient synthesis techniques,increasing the specific surface area of carbon material and obtaining carbon material with suitable pore size distribution are one of the main directions for the development of carbon electrode materials.In this paper,the porous carbon derived from pine pollen with natural pollen morphology,uniform particle size and reasonable pore size was successfully synthesized by a simple chemical activation method,grinding,high temperature calcination and acid washing.The microstructure,chemical composition and pore structure of the material were analyzed and characterized by SEM,XRD,XPS and BET;the electrochemical performance of material was studied and analyzed by the construction of a three-electrode system;finally,the symmetrical supercapacitor was prepared by the material.The performance of the supercapacitor was studied by cyclic voltammetry curve,galvanostatic charge-discharge curve,electrochemical impedance spectroscopy and Ragone curve.The specific work contents are as follows:1.Carbon materials with high specific surface area(1645.88 m2g-1),suitable pore size（～3.93nm）,a small amount of sulfur doped（0.64wt%）and a small amount of nitrogen doped（1.63wt%）were prepared by using pine pollen as precursor,copper chloride dihydrate as activator and adjusting the ratio of activator and activation temperature.2.A three-electrode system test was performed by using pin pollen derived carbon as the working electrode,Hg/Hg O electrode as the reference electrode and platinum electrode as the counter electrode.When the current density is 1 A g-1,the specific capacitance of this material can reach 334.86 F g-1.When the current density rises to10 A g-1,it still has a specific capacitance of 242.80 F g-1,which is only 72.54%of that at 1 A g-1.3.In order to verify the practical application of pine pollen derived carbon,symmetrical supercapacitor was prepared and its electrochemical performance was tested.When the current density is 1 A g-1,the specific capacitance can reach 40.61 F g-1.When the current density is increased to 10 A g-1,the specific capacitance can still reach 35.30 F g-1,which is 86.92%of 1 A g-1.At the same time,it has high energy density of 5.85 Wh kg-1 and high-power density of 5.88 k W kg-1.It has certain application possibility. |
