Metal–Organic Frameworks as Highly Active Electrocatalysts for High-Energy Density, Aqueous Zinc-Polyiodide Redox Flow Batteries

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• 作者：Bin Li ; Jian Liu ; Zimin Nie ; Wei Wang ; David Reed ; Jun Liu ; Pete McGrail ; Vincent Sprenkle
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：July 13, 2016
• 年：2016
• 卷：16
• 期：7
• 页码：4335-4340
• 全文大小：424K
• 年卷期：0
• ISSN：1530-6992

文摘

The new aqueous zinc-polyiodide redox flow battery (RFB) system with highly soluble active materials as well as ambipolar and bifunctional designs demonstrated significantly enhanced energy density, which shows great potential to reduce RFB cost. However, the poor kinetic reversibility and electrochemical activity of the redox reaction of I₃^–/I^– couples on graphite felts (GFs) electrode can result in low energy efficiency. Two nanoporous metal–organic frameworks (MOFs), MIL-125-NH₂ and UiO-66-CH₃, that have high surface areas when introduced to GF surfaces accelerated the I₃^–/I^– redox reaction. The flow cell with MOF-modified GFs serving as a positive electrode showed higher energy efficiency than the pristine GFs; increases of about 6.4% and 2.7% occurred at the current density of 30 mA/cm² for MIL-125-NH₂ and UiO-66-CH₃, respectively. Moreover, UiO-66-CH₃ is more promising due to its excellent chemical stability in the weakly acidic electrolyte. This letter highlights a way for MOFs to be used in the field of RFBs.