关键词: 木质素, KOH活化, 多孔炭, 超级电容器

Abstract: Using enzymatic lignin as raw material, porous lignin based carbon materials were constructed by optimizing the KOH activation process. The effects of parameters such as  carbon-alkali ratio,  activation temperature and activation time on the structure of lignin-|based porous carbon materials were studied   by using a one-step activation method. We tested the electrochemical properties of the prepared materials in a three-electrode system and assembled symmetrical supercapacitors by using KOH as the electrolyte to test the cycling stability of the material during continuous charge and discharge processes. The results show that  when the  activation temperature is 700 ℃,  the carbon-alkali ratio is 4∶1,  and the activation time is 2 h,  a porous carbon sample (ELC_700-2-4) with a high specific surface area (3 067 m²/g) and high microporosity (62.18%) can be prepared. In the three-electrode system,  the material exhibits excellent electrochemical performance in KOH as the electrolyte,  and the specific capacitance can reach 443 F/g at 1 A/g. The specific capacitance of ELC_700-2-4 electrode is 250 F/g at 1 A/g,  and the capacitance retention rate after 10 000 cycles is 95.55%,  indicating that the electrode has excellent cycling stability during continuous charging and discharging. The energy density of symmetrical capacitor is  8.6 W.h/kg when the power density is 500.16 W/kg. 

Key words: lignin,  , KOH activation,  , porous carbon,  , supercapacitor