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: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=649894
• 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.**

该研究计划侧重于电化学能源系统先进材料的基础研究。特别是金属/金属合金纳米颗粒、先进碳材料以及金属纳米颗粒与这些碳的组合。此类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。如果能够提高材料的性能成本比及其耐用性，这些技术就有可能在能源领域得到更广泛的应用。除了材料本身的改进之外，还需要改进诊断工具，以便能够轻松评估电极健康状况的多个指标。******该提案的重点是新型电极材料和电极材料的研究和增强。电化学阻抗谱 (EIS) 测量的改进作为首选诊断工具。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。 EIS 曲线的特定变化在降解时发生，这是特定催化剂层降解过程的特征，包括碳载体和离聚物的降解。此外，我们修改了传输线 EIS 模型，以便可以将双层电容 (Cdl) 与源自 Pt 上 Hupd 的法拉第赝电容 (CF) 分开。此外，我们已经能够证明，源自 Hupd 的 CF 大小与 Pt 表面积成正比，从而产生与电势相关的常数，从而能够通过 EIS 测量准确测量多晶 Pt 电极的电化学活性表面积。* *****这套基于 EIS 的工具在研究电极的稳定性以及典型 Pt/C 电极以外的应用中的表面工艺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型电极材料上，利用 EIS 来阐明电极表面如何随时间变化，并量化金属和碳基活性表面物种，以及这如何影响活性。长期目标包括检查结构与相关性能（例如电导率、电化学活性表面积、催化活性、容量和性能）之间的关系。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与电极表面结合的电化学可寻址氧化还原物质的定量。**