Controllable Synthesis Of Porous Carbon Materials By Template Method And Their Application As The Supercapacitor Electrode Materials

Currently,the limited sources of fossil fuels and the global warming have severely restricted the green and sustainable development of the industrial ecology and global economy.Supercapacitors have become a hot research topic in energy storage in recent years owing to its excellent perfoemance.In this regard,carbon based materials have become the most commonly used electrode for supercapacitors due to their abundant resources,good electrical conductivity,excellent chemical stability,and large specific surface area.The results show that the performance of the supercapacitor is closely related to the specific surface area,pore size distribution and the structure of surface of the electrode material.In recent years,the main reason for limiting the large-scale commercial production of supercapacitors is the low energy density,which can be improved by increasing specific capacitances and broadening the voltage windows.The porous carbon prepared by the traditional method is mainly made up of microporous,which is not conducive to the rapid transmission of large-size electrolyte.In view of this,the paper starts with the preparation method of electrode materials,and studies the influence of different pore size distribution,specific surface area and microscopic morphology on the performance of supercapacitors,as well as the different performance in different electrolytes.The main contents and results including the following aspects:?1?The TC-1-based supercapacitor prepared with MgO as template showed excellent performance in 1 M Li₂SO₄ electrolyte.The voltage windows can reach to 1.6 V and possess a specific capacitance of 173 F/g at the current density of 1 A/g,and the current density increases to 30 A/g the specific capacitance is 105 F/g,and the specific capacitance retention is 60.3%.The TC-1-based supercapacitor can deliver a high energy density of 15Wh/kg?at the power density of 400 W/kg?,and the energy density can be retained at 8Wh/kg even at a much higher power density?1.2 kW/kg?.?2?Solid-state reaction at room temperature followed by chemical activation produce K₂CO₃ as the template,the obtained hierarchically porous carbon materials showed excellent performance in 1 M Li₂SO₄ electrolyte,eg.the specific capacitance is 226 F/g at0.5A/g.The voltage windows can reach to 1.6 V,and the symmetric device based on EDTA-3K can deliver a high energy density of 20.11 Wh/kg?at the power density of 200W/kg?,and the energy density can be retained at 12 Wh/kg even at a much higher power density?1.2 kW/kg?.The first solid-state reaction between EDTA and KOH at room temperature is an efficient way to achieve the even dispersion of the activating agent within carbon source and thus improve the utilization ratio of KOH greatly.Such as the SSA can reach to 3614 m²/g even at an ultralow KOH/char ratio?0.58?.the outstanding performance benefited from the ultrahigh specific surface area,hierarchically porous structure and unique morphology.?3?A facile one-step Zn involved self-sacrificing template combined with KOH activation strategy has been developed for the producing porous carbon frameworks?PCFs?.The PCF-1 based supercapacitor in 1 M Li₂SO₄ electrolyte owns a large specific capacitance of223 F/g at 1 A/g and still remain a large value of 131 F/g at 30 A/g.The largest energy density up to 19.78 Wh/kg at a power density of 400 W/kg,the energy density still retains a large value of 11.67 Wh/kg at high power density of 1.2 kW/kg.The excellent electrochemical properties of supercapacitor benefit from its optimized pore structure and large specific surface area,which is in favour of rapid ionic mass transport.In this way,this 3D porous carbon framework with large specific surface area and abundant mesopores could subsequently facilitate rapid adsorption/desorption of electrolyte ions even at large current densities.