The typical method for preparing the porous carbon used in supercapacitors(SCs)is time-consuming and energy-intensive.We report a fast and efficient route to synthesize and tailor the structure of porous carbon by a J...The typical method for preparing the porous carbon used in supercapacitors(SCs)is time-consuming and energy-intensive.We report a fast and efficient route to synthesize and tailor the structure of porous carbon by a Joule heating technique(JHT)using phenolic resin and precursors.During the JHT process,the time and energy needed are both significantly reduced because the precursor is heated to the target temperature at a rate of 1100 K/s,so the porous carbon is formed with the release of small molecules and the etching of the substrate by K_(2)CO_(3).JHT has a higher energy efficiency than traditional carbonization methods in a tube furnace and allows for precise control of the pyrolysis process,thus achieving better control of the material’s structure and properties.Samples obtained by JHT contain abundant pores and a large specific surface area(1652.7 m^(2)/g),which give an excellent specific capacitance of 476.0 F/g and rate capability(75.1%capacitance retention at 64.0 A/g in an aqueous alkaline electrolyte).Furthermore,in electrolytes of 17.0 mol/kg NaClO_(4)(water-in-salt)and 1.0 mol/L TEABF4/AN,the symmetric SCs have a maximum energy density of 33.3 and 50.8 Wh/kg at power densities of 220.4 and 376.4 W/kg,respectively.The cells also have good long-term stability,with a nearly 100%Coulombic efficiency,and a capacitance retention of 93.1%in a water-in-salt electrolyte after 10000 cycles,and 88.9%in an organic electrolyte after 8000 cycles.This study shows that JHT has the potential to serve as an ultra-fast method to prepare porous carbons for energy storage.展开更多
文摘The typical method for preparing the porous carbon used in supercapacitors(SCs)is time-consuming and energy-intensive.We report a fast and efficient route to synthesize and tailor the structure of porous carbon by a Joule heating technique(JHT)using phenolic resin and precursors.During the JHT process,the time and energy needed are both significantly reduced because the precursor is heated to the target temperature at a rate of 1100 K/s,so the porous carbon is formed with the release of small molecules and the etching of the substrate by K_(2)CO_(3).JHT has a higher energy efficiency than traditional carbonization methods in a tube furnace and allows for precise control of the pyrolysis process,thus achieving better control of the material’s structure and properties.Samples obtained by JHT contain abundant pores and a large specific surface area(1652.7 m^(2)/g),which give an excellent specific capacitance of 476.0 F/g and rate capability(75.1%capacitance retention at 64.0 A/g in an aqueous alkaline electrolyte).Furthermore,in electrolytes of 17.0 mol/kg NaClO_(4)(water-in-salt)and 1.0 mol/L TEABF4/AN,the symmetric SCs have a maximum energy density of 33.3 and 50.8 Wh/kg at power densities of 220.4 and 376.4 W/kg,respectively.The cells also have good long-term stability,with a nearly 100%Coulombic efficiency,and a capacitance retention of 93.1%in a water-in-salt electrolyte after 10000 cycles,and 88.9%in an organic electrolyte after 8000 cycles.This study shows that JHT has the potential to serve as an ultra-fast method to prepare porous carbons for energy storage.
