本文選題：勝利褐煤　切入點(diǎn)：活性炭　出處：《中國礦業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：本論文以勝利褐煤為原料,KOH為活化劑,采用炭化活化法和HNO_3表面氧化改性法制備活性炭,采用掃描電子顯微鏡(SEM)、X射線衍射(XRD)、N2等溫吸脫附、傅里葉變換紅外光譜(FTIR)和X射線光電子能譜(XPS)等表征活性炭結(jié)構(gòu)及表面性質(zhì)。將所制備活性炭用于雙電層電容器(EDLC)的電極材料,通過恒流充放電、循環(huán)伏安和交流阻抗等方法測試活性炭電極的電化學(xué)性能。重點(diǎn)考察了活性炭制備條件和HNO_3表面氧化改性對勝利褐煤基活性炭比表面積、孔結(jié)構(gòu)及其電化學(xué)性能的影響。電化學(xué)性能測試表明,不同制備條件下的活性炭電極在6 mol L-1 KOH電解液中具有良好的充放電性能,且KOH體系下的比電容高于有機(jī)體系下的比電容。結(jié)果發(fā)現(xiàn),增大活性炭的表面積可以提高活性炭電極的比電容,但兩者不是簡單的線性關(guān)系。比電容隨著電流密度的增大呈現(xiàn)出不同程度的衰減,并且在高電流密度下具有較高的比電容保持率,表現(xiàn)出較好的大電流放電特性。經(jīng)700 ℃炭化,800 ℃活化2 h(KOH/樣品為4)制備的活性炭AC-K-4的比表面積為2550 m2g-1,孔容為1.24 cm3 g-1,比電容在電流密度是40 mA g-1時達(dá)到213 F g-1,200mA g-1時保持在175 F g-1。并且,該電極具有良好的循環(huán)穩(wěn)定性,充放電循環(huán)1000次后,充放電效率保持在96%左右,表明制備的勝利褐煤基活性炭是EDLC適宜的電極材料。對活性炭進(jìn)行HNO_3氧化改性,活性炭的比表面積和孔容有所降低,但增加了活性炭表面的含氧官能團(tuán),其中羥基和羧基含量增加最為明顯。結(jié)果表明,60%HNO_3改性的活性炭電極AC-K-4在40 mA g-1時的比電容增加到245 F g-1,且活性炭表面引入的含氧官能團(tuán)使其的潤濕性有所增加,電荷遷移電阻和漏電流有所降低,進(jìn)而提高了活性炭電極的能量密度。
[Abstract]:In this paper, activated carbon was prepared by carbonization activation and surface oxidation modification of HNO_3 with Shengli lignite as raw material and Koh as activator. The adsorption and desorption of activated carbon by scanning electron microscope (SEM) were studied by X-ray diffraction (XRD) and X-ray diffraction (XRD). Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure and surface properties of activated carbon. The electrochemical performance of activated carbon electrode was measured by cyclic voltammetry and AC impedance. The preparation conditions of activated carbon and the specific surface area of Shengli lignite based activated carbon modified by HNO_3 surface oxidation were investigated. The effects of pore structure and electrochemical properties on the electrochemical properties of activated carbon electrode were investigated. The results showed that the activated carbon electrode prepared under different conditions had good charge-discharge performance in 6 mol L-1 KOH electrolyte. The specific capacitance in KOH system is higher than that in organic system. The results show that the specific capacitance of activated carbon electrode can be increased by increasing the surface area of activated carbon. But the two are not simple linear relations. The specific capacitance attenuates with the increase of the current density, and has a higher specific capacitance retention rate under the high current density. The activated carbon AC-K-4 prepared at 700 鈩，

本文編號：1638728