کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6603695 | 1424088 | 2018 | 25 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Capacitance enhancement of hybrid electrochemical capacitor with asymmetric carbon electrodes configuration in neutral aqueous electrolyte
ترجمه فارسی عنوان
افزایش ظرفیت خازن الکتروشیمیایی ترکیبی با تنظیم الکترودهای کربن نامتقارن در الکترولیت آب خنک
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
مهندسی شیمی (عمومی)
چکیده انگلیسی
A hybrid electrochemical capacitor in 1â¯molâ¯Lâ1 Li2SO4 + 0.2 mol Lâ1 KI aqueous solution (pHâ¯=â¯6.5, conductivityâ¯=â¯86â¯mSâ¯cmâ1 at 24â¯Â°C) has been developed by implementing highly microporous carbon (KAC, average micropore size L0â¯=â¯0.88â¯nm) as negative electrode and a micro-/mesoporous carbon (PAC, average micropore size L0â¯=â¯1.01â¯nm) as positive electrode. Under negative polarization, KAC demonstrates a high electrical double-layer (EDL) capacitance (187â¯Fâ¯gâ1), owing to strictly microporous texture making it suitable as negative electrode in a hybrid cell. Besides, under positive polarization, a well-defined faradaic redox signature (in narrow potential range) related with the iodine/iodide system is observed with PAC, giving rise to much higher capacity (62â¯mAh gâ1) than with KAC (37â¯mAh gâ1) and making the former a good candidate to be implemented as positive electrode in a hybrid cell. As a result, the asymmetric (â)KAC/PAC(+) hybrid cell in aqueous Li2SO4+KI exhibits a high capacitance of 74 F gâ1 (per total active mass of the two electrodes) compared to 66â¯Fâ¯gâ1 and 50â¯Fâ¯gâ1 for the (â)KAC/KAC(+) and (â)PAC/PAC(+) hybrid cells, respectively. Moreover, for the asymmetric (â)KAC/PAC(+) capacitor, the potential of the positive electrode is lower than the thermodynamic limit of water oxidation, and the potential of the negative electrode is higher than the kinetic limit of hydrogen evolution. Consequently, the asymmetric (â)KAC/PAC(+) hybrid cell demonstrates the lowest capacitance drop and resistance increase during floating. At 2.5 A gâ1, the (â)KAC/PAC(+) capacitor exhibits a high specific energy of 15.4 Wh kgâ1 compared to 10.1â¯Wh kgâ1 and 8.1â¯Wh kgâ1 for the (â)KAC/KAC(+) and (â)PAC/PAC(+) capacitors, respectively. Raman spectra on the PAC positive electrode of the asymmetric (â)KAC/PAC(+) cell demonstrate upshifting of D and G bands by 12 cmâ1 and 8â¯cmâ1, respectively, suggesting a charge transfer between carbon and polyiodides confined in the porosity.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Electrochimica Acta - Volume 269, 10 April 2018, Pages 640-648
Journal: Electrochimica Acta - Volume 269, 10 April 2018, Pages 640-648
نویسندگان
Patryk Przygocki, Qamar Abbas, François Béguin,