Understanding the activity and stability of electrode materials targeted for clean energy applications through diagnostic impedance measurements

通过诊断阻抗测量了解清洁能源应用电极材料的活性和稳定性

• 批准号: RGPIN-2015-03652
• 负责人: Easton, EBradley
• 金额: $ 3.28万
• 依托单位: University of Ontario Institute of Technology
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=612482
• 关键词: Understanding; activity; stability; electrode; materials

This research program focuses on fundamental studies of advanced materials targeted for electrochemical energy systems. Specifically metal/metal-alloy nanoparticles, advanced carbon materials as well as combinations of metals nanoparticles with these carbons. Such materials are at the heart of numerous electrochemical energy technologies, including fuel cells, electrolyzers and electrochemical/super capacitors. These technologies have the potential to be more widely deployed in the energy landscape provided that improvements can be made in the performance-to-cost ratio of the materials, and also in their durability. In addition to improvements in the materials themselves, improvements are needed in diagnostic tools that can readily assess multiple indicators of the electrode state-of-health. This proposal is focused on the study and enhancement of new electrode materials and the refinement of electrochemical impedance spectroscopy (EIS) measurements as a go-to diagnostic tool. We have recently developed an EIS-based diagnostic methods that can clearly elucidate the mode of electrode degradation occurring. Specific changes in the EIS profiles occur upon degradation that are characteristic of specific catalyst layer degradation processes, including the degradation of the carbon support and the ionomer. Furthermore, we have modified the transmission line EIS model so that double-layer capacitance (Cdl) can be separated from faradaic pseudo-capacitance (CF) originating from Hupd on Pt. Moreover, we have been able to show that magnitude of CF originating from Hupd is proportional to the Pt surface area, yielding potential-dependent constants that enable accurate measurements of the electrochemically active surface area of a poly-crystalline Pt electrodes from EIS measurements. Together this suite of EIS-based tools has enormous potential to study both the stability of an electrode and also surface processes in applications beyond typical Pt/C electrodes. Thus, our ongoing studies will focus on novel electrode materials, employing EIS to elucidate how the electrode surface is changing over time and also to quantify active surface species, both metallic and carbon-based, and how this impacts activity. Longer-term objectives include an examination of the relationships between structure and relevant properties such as conductivity, electrochemically active surface area, catalytic activity, capacity and performance. Furthermore, we will seek to extend our EIS methodology so that it can be applied universally in the quantification of electrochemically addressable redox species bound to an electrode surface.

这项研究计划侧重于针对电化学能源系统的先进材料的基础研究。特别是金属/金属合金纳米粒子、先进的碳材料以及金属纳米粒子与这些碳的组合。这种材料是众多电化学能源技术的核心，包括燃料电池、电解槽和电化学/超级电容器。这些技术有可能在能源领域得到更广泛的部署，前提是这些材料的性价比和耐用性都能得到改善。除了材料本身的改进外，还需要改进能够容易地评估电极健康状态的多个指标的诊断工具。 这项建议的重点是研究和加强新的电极材料和完善的电化学阻抗谱(EIS)测量作为一种首选的诊断工具。我们最近开发了一种基于EIS的诊断方法，可以清楚地阐明电极退化发生的模式。当特定催化剂层降解过程的特征，包括碳载体和离聚体的降解时，EIS图谱发生特定的变化。此外，我们还对传输线EIS模型进行了修正，使得双层电容(CDL)可以与铂上HUPD产生的法拉第伪电容(CF)分离开来。此外，我们已经能够证明来自HUPD的CF的大小与铂的表面积成正比，产生的电位依赖的常数使得能够从EIS测量中准确地测量多晶铂电极的电化学活性表面积。 总而言之，这套基于EIS的工具在研究电极的稳定性以及典型铂/碳电极以外的应用中的表面过程方面具有巨大的潜力。因此，我们正在进行的研究将集中在新的电极材料上，利用EIS来阐明电极表面如何随着时间的变化而变化，并量化金属和碳基的活性表面物种，以及这如何影响活性。较长期的目标包括审查结构和相关性质之间的关系，如导电性、电化学活性表面积、催化活性、容量和性能。此外，我们将寻求扩展我们的EIS方法，以便它可以普遍应用于电极表面结合的电化学可寻址氧化还原物种的定量。