【摘要】 以农业废料稻壳为碳源,氢氧化钠为活化剂,采用干法两步活化法制备活性炭。X射线衍射分析表明该法能有效去除稻壳中的灰分,提高活性炭的孔隙率。扫描电镜结果表明,活性炭具有发达的孔隙结构。以活性炭制备超级电容器的电极,并组装成扣式电容器。采用恒流充放电、循环伏安、交流阻抗等测定超级电容器的电化学性能,并着重探究了预活化时间对活性炭的结构及电化学性能的影响。结果表明,预活化时间为120 min的活性炭的比电容最大,在0.25 A/g电流密度下,可达219F/g,经过1 000次循环后,其电容保持率仍达85.4%。这表明活性炭电极具有较理想的电容特性,且循环性能稳定。更多还原

【Abstract】 In this paper,agricultural waste rice husk as carbon source,sodium hydroxide as activator,dry two-step activation was used to prepare activated carbon.The results of X-ray diffraction(XRD)showed that this activation method could effectively remove ash from rice husk and improve the porosity of activated carbon.Scanning electron microscopy(SEM)revealed that the activated carbon has a developed pore structure.And then the electrode of supercapacitor was prepared with activated carbon and assembled into a button capacitor.The electrochemical performance of supercapacitor was measured by constant current charging-discharging,cyclic voltammetry(CV)and alternating current(AC)impedance.In addition,the effect of pre-activation time on structure and electrochemical properties of activated carbon was investigated.The results showed that the activated carbon with the pre-activation time of 120 min possessed the largest specific capacitance of 219 F/g at 0.25 A/g for current density.And the capacitance retention rate was as high as 85.4% after 1 000 cycles,indicating that the activated carbon electrode had ideal capacitance characteristics and stable cycling performance.更多还原