Experimental and Modeling Studies on Redox Flow Batteries

鉴于不断增长的人口和工业化，以及向可再生能源的转变，对能源储存系统的需求从未像现在这样高。这些系统在特定时间段存储剩余能量，并在其他时间按需释放，使电网能够更好地将可再生能源与基本负载能量整合在一起，并对扰动具有更强的鲁棒性。不幸的是，目前几乎没有可用的存储方法，因此全球只有不到10%的电力来自存储能量。*电化学方法由于其无污染操作、快速响应、高效率、灵活性、便携性和低维护而有望填补这一空白。在这些方法中，氧化还原液流电池(RFB)脱颖而出。和其他电池一样，电极被装在单独的隔间里。与传统电池不同，反应物溶解在储存在外部储罐中的液体电解液中，并持续泵入发生氧化还原反应的隔间。这些特点使RFBS比其他电池具有优势：独立控制能量和功率、固有的安全性、快速和可逆氧化还原反应、无固态效应、易于热管理、无过热、无电解液击穿和长寿命。然而，有两个主要因素阻碍了它们的采用：安装成本高和耐用性问题。*本研究计划致力于提高锌-铈和钒-铈两种相对较新的RFB系统的性能和耐用性，同时降低成本。Ce~(3+)/Ce~(4+)反应在两种RFB的正电极上进行，而锌/锌和V~(2+)/V~(3+)反应在负电极上进行。这些系统非常有前景，因为它们获得了比其他RFB更高的电池电压和潜在的更高的能量和功率。拟议的研究将包括i)旨在抑制寄生副反应并提高电池性能和耐用性的小规模实验，以及ii)为每个电池开发一个全面的模型。研究的新方面包括在两个隔室中使用混合酸，用高活性的改性碳材料取代昂贵的铂正电极，用阴离子交换膜取代传统的Nafion膜，以及在V-Ce RFB中使用零间隙流动电池。*鉴于它们的优势和缺乏可行的替代方案，如果该计划中解决的关键挑战被攻克，锌-Ce和V-Ce RFB有望在储能技术上取得突破。加拿大通过示范单位的运作和风险资本投资，在RFB的发展中发挥了重要作用。拟议研究的成功将有助于保持加拿大在这一领域的突出地位。参与研究的四名研究生将学习广泛的尖端实验和建模技能，使他们能够在学术界或能源/制造业追求成功的职业生涯。*

Given growing populations and industrialization and the shift toward renewable energy, the need for energy storage systems has never been higher. These systems store surplus energy during certain periods and discharge it on demand at other times, enabling the electrical grid to better integrate renewables with base load energy and be more robust to disturbances. Unfortunately, few storage methods are currently available and so less than 10% of the total delivered electric power worldwide comes via energy storage.****Electrochemical methods are well poised to fill this gap due to their pollution-free operation, fast response, high efficiency, flexibility, portability and low maintenance. Among these methods, redox flow batteries (RFB) stand out. The electrodes are contained in separate compartments as in other batteries. Unlike conventional batteries, the reactants are dissolved in liquid electrolytes stored in external tanks and pumped continuously through their compartments where the redox reactions occur. These features give RFBs advantages over other batteries independent control of energy and power, inherent safety, fast and reversible redox reactions, no solid-state effects, easy thermal management, no overheating, no electrolyte breakdown and long lifetimes. However, two main factors have hindered their adoption high installed cost and durability concerns. ***This research program focuses on improving the performance and durability while reducing the cost of two relatively new systems zinc-cerium and vanadium-cerium RFBs. The Ce3+/Ce4+ reaction operates at the positive electrode in both RFBs, while Zn/Zn2+ and V2+/V3+ operate at the negative electrodes. These systems are very promising since they attain higher cell voltages and potentially much higher energy and power than other RFBs. The proposed research will include i) bench-scale experiments aimed at suppressing parasitic side reactions and enhancing cell performance and durability and ii) development of a comprehensive model for each battery. Novel aspects of the research are the use of mixed acids in both compartments, replacement of expensive Pt positive electrodes with highly active modified carbon materials, replacement of conventional Nafion membranes with anion exchange membranes and use of a zero-gap flow-through cell for the V-Ce RFB.****Given their advantages and the lack of viable alternatives, the Zn-Ce and V-Ce RFBs are poised for a breakthrough in energy storage technology, provided the key challenges addressed in this program are overcome. Canada has played an important role in RFB development via the operation of demonstration units and venture capital investment. Success in the proposed research will help maintain Canada's prominence in this sector. The four graduate students involved in the research will learn a broad suite of cutting-edge experimental and modeling skills that will enable them to pursue successful careers in academia or the energy/manufacturing sectors.***