| Because of their high power density and fast charging ability,supercapacitors are widely used in high-power power supply occasions;based on their advantages of high power density,improving the energy density of supercapacitors is the focus of research at home and abroad.In the past ten years,most researches on the energy density of supercapacitors have focused on their mass energy density.With the rise of electric vehicles and the increasing demand for portable energy supply,high energy density(ie,volumetric energy density)in limited space The realization of urgent needs.Carbon-based electrode materials are an important component of supercapacitors.While maintaining their mass energy density,the optimization of pore structure and the improvement of electrode density are the keys to achieving volumetric energy density enhancement.Coal is a natural carbon source with large reserves and high carbon content.The activated carbon material prepared by physical or chemical activation is an important choice for supercapacitor electrode materials due to its high specific surface area and adjustable pore structure.The power density of coal-based activated carbon is an important direction for synergistically enhancing the utilization value of coal resources and developing high-performance supercapacitor energy storage devices.This article focuses on the realization of the volumetric energy density of coal-based activated carbon supercapacitors,and deeply explores the depth control methods of typical activation and post-treatment processes on the pore structure and electrode density of coal-based activated carbon.The impact of the capacitor’s compact energy storage characteristics.In order to further improve the volume capacity characteristics of porous activated carbon materials and solve the contradictory relationship between material density and mass specific capacitance,this article selects three typical high specific surface area porous activated carbons as raw materials,ball milled for 2,4,6,and 8 hours,and their structure was optimized by ball milling at multiple scales.The physical and chemical structure of porous carbon was analyzed by scanning electron microscopy,low temperature nitrogen adsorption test,Raman spectroscopy,XRD,etc.,and the multi-scale effects of the ball milling process on the porous activated carbon from micro-functional groups,pore structure to macro-density were explored.After 4 hours of alkaline oxygen oxidation pretreatment of the ball mill,the oxygen content of the activated carbon increased from 4.77% to 14.5%,the specific surface area decreased from about 2900 m2 g-1 to about 100 m2 g-1,and the tap density increased from 0.07 g cm-3 To 0.47 g cm-3,the electrode density increased from 0.58 g cm-3 to 0.47 g cm-3,and its mass specific capacitance decreased from 214 F g-1 to 171 F g-1,and finally its volume specific capacitance was as high as 242 F cm-3 is 3-4 times that of current commercial activated carbon.At the same time,in order to analyze the impact process of the ball milling process on the porous activated carbon particles,this paper uses discrete element EDEM software to simulate the ball milling process,analyze the information such as the motion state speed of the ball material during the ball milling process,and describe the ball milling process in terms of speed,collision energy,and force,To provide analytical means for the experiment. |
