Chemical Stability of Graphite-Polypropylene Bipolar Plates for the Vanadium Redox Flow Battery at Resting State
Chemical Stability of Graphite-Polypropylene Bipolar Plates for the Vanadium Redox Flow Battery at Resting State
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DOI：
10.1149/2.0841610jes
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发表时间：
2016
影响因子：
3.9
通讯作者：
Barbara Satola;C. Kirchner;L. Komsiyska;G. Wittstock
中科院分区：
文献类型：
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作者：
Barbara Satola;C. Kirchner;L. Komsiyska;G. Wittstock
集流体称为双极板（BPP），是钒氧化还原低电压电池（VRFB）的转换单元内的重要元件。它们与酸性电解液直接接触，含有不同氧化态的钒物质。考察了荷电状态（SOC）对BPP日历老化的影响。将石墨-聚丙烯BPP在0%、20%、80%和100%SOC下浸入正极和负极钒电解液中30、90和190天。在负极电解液中，BPP表面上观察到H2气体析出作为副反应。无电老化后，扫描电子（SEM）和共聚焦显微镜测量显示表面形态没有显著变化。BPP的电导率没有受到显著影响。接触角（θ）的测定结果表明，正极电解液对BPP的润湿性没有明显影响。X射线光电子能谱（XP）表明，在正电解质和吸附或捕获的钒离子在孔隙中的高SOC的BPP表面进行氧化。循环伏安（CV）提供的证据表明，石墨被氧化结合在有效表面积的增加。ATR-FTIR测量显示，纯聚丙烯在100%SOC的正极电解液中发生轻微氧化。©间歇性可再生能源的能源供应不断增加，需要快速引入有效的能量存储。一种有前途的技术是钒氧化还原低电压电池（VRFB），因为它能够根据具体要求独立扩展功率和存储容量。1，2此外，VRFB的特点是响应时间快，电解液循环寿命长。3 VRFB堆中的每个反应单元由两个半电池组成，所述两个半电池由膜隔开，所述膜由与称为双极板（BPP）的集电器接触的电极组成。2在电池组中，BPP是将电流从一个电池传导到另一个电池的“非有源”组件。它们将相邻电池彼此物理分离，同时保持与每侧上含有不同氧化态的钒物质的酸性半电池电解质接触。4
Current collectors called bipolar plates (BPP) are important elements within the conversion unit of the vanadium redox flow battery (VRFB). They are in direct contact with acidic electrolytes, containing vanadium species in different oxidation states. The influence of the state of charge (SOC) on the calendar aging of BPPs was examined. Graphite-polypropylene BPPs were immersed in positive and negative vanadium electrolytes at 0%, 20%, 80% and 100% SOC for 30, 90 and 190 days. H 2 gas evolution was observed as side reaction on the surface of the BPPs in the negative electrolyte. After electroless aging, scanning electron (SEM) and confocal microscopy measurements showed no significant changes in the surface morphology. The electrical conductivities of the BPPs were not affected significantly. However, contact angle ( θ ) measurements revealed that the positive electrolyte influenced the wettability of the BPPs. X-ray photoelectron (XP) spectroscopy showed progressing oxidation of the BPP surfaces in the positive electrolyte and adsorption or entrapment of vanadium ions in the pores at high SOC. Cyclic voltammograms (CV) provided evidence that the graphite was oxidized combined with an increase in effective surface area. ATR-FTIR measurements showed slight oxidation of pure polypropylene granulate in the positive electrolyte with 100% SOC. © The increasing energy power supply from intermittent renewable energy sources requires a rapid introduction of efficient energy stor-ages. One promising technology is the vanadium redox flow battery (VRFB), as it enables to scale the power and the storage capacity independently according to specific requirements. 1,2 In addition the VRFB is characterized by a fast response time and long electrolyte cycle life. 3 Each reaction unit in a VRFB stack is composed of two half-cells separated by a membrane consisting of an electrode in con- tact with a current collector called bipolar plate (BPP). 2 In a battery stack the BPPs are “non-active” components that conduct current from one cell to the other. They physically separate adjacent cells from each other while staying in contact with acidic half-cell electrolytes con- taining vanadium species in different oxidation states on each side. 4