Study of the Ce3+/Ce4+ Redox Couple in Mixed-Acid Media (CH3SO3H and H2SO4) for Redox Flow Battery Application

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• 作者：Zhipeng Xie ; Fengjiao Xiong ; Debi Zhou
• 刊名：Energy & Fuels
• 出版年：2011
• 出版时间：May 19, 2011
• 年：2011
• 卷：25
• 期：5
• 页码：2399-2404
• 全文大小：797K
• 年卷期：v.25,no.5(May 19, 2011)
• ISSN：1520-5029

文摘

The present paper first reports a kind of supporting electrolyte, mixed-acid media (CH₃SO₃H and H₂SO₄), used in redox flow battery (RFB) technology. Experimental work is performed with the aim of evaluating the Ce³⁺/Ce⁴⁺ redox couple in mixed-acid electrolyte for use in RFB technology. The mixed-acid media have their special advantages: (i) the Ce³⁺/Ce⁴⁺ electrode reaction appears to be more reversible in mixed-acid solution; the peak splittings in mixed acid are significantly less than in sulfuric acid; the diffusion coeffcient in mixed acid is larger than in single acid (CH₃SO₃H or H₂SO₄); the exchange current density and standard rate constant of the Ce³⁺/Ce⁴⁺ redox reaction in mixed-acid media on graphite electrode are 8.05 脳 10^鈥? A cm^鈥? and 4.17 脳 10^鈥? cm s^鈥?; (ii) the solubility of cerium salt in mixed acid is larger than in sulfuric acid; a solution of 1 mol dm^鈥? cerium containing 2 mol dm^鈥? MSA and 0.5 mol dm^鈥? H₂SO₄ is sufficiently stable for more than 1 month at temperatures up to 313 K; (iii) Coulombic and energy efficiencies of the test cell using mixed-acid electrolyte are both higher than that using single CH₃SO₃H electrolyte; the average Coulombic and energy efficiencies of the cell using mixed acid are 87.1 and 73.5%, respectively, which are comparable to that of the all-vanadium RFB.