کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7832658 | 1503301 | 2006 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Investigations on the Electrode Process of Concentrated V(IV)/V(V) Species in a Vanadium Redox Flow Battery
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The electrode process of concentrated V(IV)/V(V) species has been studied at a graphite electrode by using cyclic voltammetry, low speed linear polarization, and impedance techniques. The results have revealed that in H2SO4 solution below 2 mol·Lâ1 containing 2.0 mol·Lâ1 V(IV), the electrode process of V(IV)/V(V) is controlled by the electrochemical polarization and diffusion with poor reversibility. When the concentration of H2SO4 is above 2 mol·Lâ1, the electrode process of V(IV)/V(V) turns to diffusion control with improvement of the reversibility. An increase in concentration of H2SO4 solution facilitates a decrease in impedance, whereas too high concentration of H2SO4 solution (>3 mol·Lâ1) results in a remarkable increase in the viscosity of solution leading to a large mass transportation polarization, and thus the impedance starts to increase a little. In 3 mol·Lâ1 H2SO4 solution, the reversibility and kinetics of V(IV)/V(V) are improved gradually and the characteristics of impedance also improves with an increase in concentration of V(IV) solution. But, when the concentration of V(IV) solution exceeds 2.0 mol·Lâ1, the viscosity of the solution is so high that the mass transportation polarization increases considerably, resulting in the deterioration of electrochemical performance of V(IV)/V(V) species and an increase in impedance. Therefore, by considering from the standpoint of increasing energy density and electrode kinetics comprehensively, the optimal concentration of H2SO4 is 3 mol·Lâ1 containing 1.5-2.0 mol·Lâ1 of V(IV).
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Physico-Chimica Sinica - Volume 22, Issue 4, April 2006, Pages 403-408
Journal: Acta Physico-Chimica Sinica - Volume 22, Issue 4, April 2006, Pages 403-408
نویسندگان
Yuehua Wen, Huamin Zhang, Peng Qian, Ping Zhao, Hantao Zhou, Baolian Yi,