以6 mol/L KOH水溶液为电解液，高比表面积的活性炭为活性物质，研究了有机添加剂对体系润湿性、电导率、工作电压窗口及阻抗的影响，测试了超级电容器的电化学性能。结果表明，适量添加有机添加剂可明显抑制体系的极化现象，提高超级电容器的工作电压窗口。添加10vol%异丙醇时，电极材料和电解液间的润湿性大幅提高，比电容从79.3 F/g提高至113.2 F/g。添加20vol%异丙醇时，超级电容器的能量密度达19.4 Wh/kg，体系的电荷转移电阻明显降低，在10 A/g电流密度下的比电容比0.5 A/g时下降13.9%，而不加添加剂时下降30.3%。添加30vol%异丙醇时，电解液电导率迅速下降，比电容降低，电导率是影响比电容的关键因素。
The components of electrolytes play an important role in determining the properties of supercapacitors. Different electrolytes have their superiority and disadvantages. Aqueous electrolyte is one of the electrolytes used in supercapacitors, but it is limited in industrialization because of its narrow voltage window and low energy density. The addition of organic solvents could enhance the performance of supercapacitors, which has gained more and more attention in this research direction. In this work, 6 mol/L KOH solution was used as the electrolyte, and the activated carbon with high specific surface area was used as electrode material. The effects of organic additives on the electrochemical performance and energy density of supercapacitors in aqueous electrolytes were investigated. The electrochemical properties of the supercapacitor were researched after adding different kinds of organic additives in the aqueous electrolyte. The results showed that the polarization phenomenon of the system can be significantly suppressed due to the addition of appropriate organic additives, the operating voltage window and energy density of the supercapacitor were improved. After 10vol% isopropanol was added to the aqueous electrolyte, the wettability between the electrode material and the electrolyte was greatly improved, and the specific capacity increased from 79.3 F/g to 113.2 F/g. Adding 20vol% isopropanol, the working voltage window of the system increased from ?0.8~0 V to ?0.8~0.5 V, the energy density of the supercapacitor reached 19.4 Wh/kg, the charge transfer resistance of the system was significantly reduced, the specific capacity decreased by 13.9% at 10 A/g than it was at 0.5 A/g while the specific capacity decreased by 30.3% without additives. However, when 30vol% isopropanol was added, since the ion transfer at the viscous electrolyte was limited, the conductivity was greatly lowered, resulting in rapid decay of the specific capacitance.
[1]孟庆函, 刘玲, 宋怀河, 等.超级电容器用复合炭极板电极的电化学性能[J].电源技术, 2004, 28(7):405-407 [2]Kim B, Chung H, Kim W.High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes[J].Nanotechnology, 2012, 23(15):155-401 [3]Wang G, Zhang L, Zhang J.A review of electrode materials for electrochemical supercapacitors[J].Chemical Society Reviews, 2012, 41(2):797-828 [4]Béguin F, Presser V, Balducci A, et al.Carbons and electrolytes for advanced supercapacitors[J].Advanced materials, 2014, 26(14):2219-2251 [5]仲皓想, 赵春宝, 骆浩, 等.一种新型有机硅离子液体电解液在超级电容器中的应用[J].物理化学学报, 2012, 28(11):2641-2647 [6]Zhong H X, Zhao C B, Luo H, et al.Application of a novel silicone ionic liquid electrolyte in supercapacitors[J].Journal of Physical Chemistry, 2012, 28(11):2641-2647 [7]穆学超, 王欣然, 郑诗礼, 等.钙掺杂钒青铜超级电容器电极材料的制备及其性能[J].过程工程学报, 2013, 13(5):882-888 [8]Mu X C, Wang X R, Zheng S L, et al.Preparation and properties of calcium-doped vanadium bronze supercapacitor electrode materials[J].Journal of Process Engineering, 2013, 13(5):882-888 [9]Lee H Y, Goodenough J B.Ideal supercapacitor behavior of amorphous V2O5· nH2O in potassium chloride (KCl) aqueous solution[J].Journal of Solid State Chemistry, 1999, 148(1):81-84 [10]Choudhury N A, Sampath S, Shukla A K.Hydrogel-polymer electrolytes for electrochemical capacitors: an overview[J].Energy & Environmental Science, 2009, 2(1):55-67 [11]温祖标, 田舒, 曲群婷, 等.以嵌入化合物为正极的混合超级电容器[J].化学进展, 2011, 23(0203):589-594 [12]Wen Z B, Tian S, Qu Q T, et al.Hybrid supercapacitor with embedded compound as positive electrode[J].Chemical progress, 2011, 23(0203):589-594 [13]Yu X, Wang J, Wang C, et al.A novel electrolyte used in high working voltage application for electrical double-layer capacitor using spiro-(1, 1′)-bipyrrolidinium tetrafluoroborate in mixtures solvents[J]., 2015, 182(8):1166-1174 [14]Zhou H, Sun W, Li J.Preparation of spiro-type quaternary ammonium salt via economical and efficient synthetic route as electrolyte for electric double-layer capacitor[J].Journal of Central South University, 2015, 22(7):2435-2439 [15]Kurig H, Vestli M, Tonurist K, et al.Influence of room temperature ionic liquid anion chemical composition and electrical charge delocalization on the supercapacitor properties[J].Journal of The Electrochemical Society, 2012, 159(7):A944-A951 [16]Kumar Y, Pandey G P, Hashmi S A.Gel polymer electrolyte based electrical double layer capacitors: comparative study with multiwalled carbon nanotubes and activated carbon electrodes[J].The Journal of Physical Chemistry C, 2012, 116(50):26118-26127 [17]West W C, Smart M C, Brandon E J, et al.Double-layer capacitor electrolytes using 1,3-D ioxolane for low temperature operation[J].Journal of the Electrochemical Society, 2008, 155(10):A716-A720 [18]Tooming T, Thomberg T, Siinor L, et al.A type high capacitance supercapacitor based on mixed room temperature ionic liquids containing specifically adsorbed iodide anions[J].Journal of the Electrochemical Society, 2014, 161(3):A222-A227 [19]黄博, 孙现众, 张熊, 等.活性炭基软包装超级电容器用有机电解液[J].物理化学学报, 2013, 29(9):1998-2004 [20]Huang B, Sun X Z, Zhang X, et al.Organic electrolytes for activated carbon-based supercapacitors with flexible package[J].Acta Physico-Chimica Sinica, 2013, 29(9):1998-2004 [21] Gromadskyi D G, Chae J H, Norman S A, et al.Correlation of energy storage performance of supercapacitor with iso-propanol improved wettability of aqueous electrolyte on activated carbon electrodes of various apparent densities[J]., 2015, 159:39-50[J]., 2015, 159(7):39-50 [22]Fic K, Lota G, Frackowiak E.Effect of surfactants on capacitance properties of carbon electrodes[J].Electrochimica Acta, 2012, 60(133):206-212 [23]Liu X M, Zhang R, Liang Z, et al.Impedance of carbon aerogelactivated carbon composites as electrodes of electrochemical capacitors in aprotic electrolyte[J].New Carbon Materials, 2007, 22(2):153-158 [24]K?tz R, Carlen M.Principles and applications of electrochemical capacitors[J].Electrochimica acta, 2000, 45(15-16):2483-2498
