The Contact Resistance of a Double-Sided MPL Coated GDL used in PEMFC

PEMFC 中使用的双面 MPL 涂层 GDL 的接触电阻

• 批准号: 2448073
• 金额: --
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2448073
• 关键词: Contact; Resistance; Double; Sided; MPL

Fuel cells are electrochemical devices that convert the chemical energy of a reaction directly into electrical energy. Proton exchange membrane fuel cells (PEMFC) are in particular, an area of substantial interest. This is due to the fact that they are very versatile. For example, they can be used in applications such as portable energy, stationary energy production and transportation. Furthermore, they potentially have an important role to play in the future "hydrogen economy". This includes contributing to reduce greenhouse gas emissions and decreasing the dependence on fossil fuel technologies. The gas diffusion layer (GDL) is a critical component in the PEMFC. The role of the GDL in the operation of a PEMFC is multifaceted. It provides a medium through which the reactant gases can diffuse through, while simultaneously allowing excess liquid water to be removed. The GDL also facilitates heat and electron transfer through the PEMFC. Additionally, it provides mechanical support for the delicate catalyst layer and membrane. The GDL is an important medium between the catalyst and bipolar plate; this has led to much research into the GDL performance. Despite this, the GDL is still an area of considerable operational losses in a PEMFC, particularly ohmic losses. These loses become more consequential at the interfacial contacts between components within the fuel cell; this is especially significant for the GDL as it sits in between the bipolar plate and catalyst layer. Electrical losses at the contact interfaces, such as, between the GDL and bipolar plate and the GDL and catalyst layer are significantly higher than individual component bulk losses. To enhance the properties of the GDL at the interfacial contact with the catalyst layer, a microporous layer (MPL) is conventionally applied. Typically, the MPL consists of carbon particles mixed with PTFE and a binder. The MPL has been proven to improve overall performance of the GDL at the catalyst layer interface, including improvements in electrical contact. The main objective of the research is to improve the performance of PEMFC by reducing the interfacial contact resistance (ICR) by the application of a double-sided MPL coated GDL. This will be achieved by coating the GDL with a double-sided MPL. One MPL will face the catalyst layer and the other will be facing the bipolar plate. Reducing ohmic losses of the PEMFC has been the focus of many research groups. However, the reduction of ohmic losses via the reduction of ICR using a double-sided MPL coated GDL is still not fully understood. Particular attention will be paid to the ex-situ characterisation measurements, as these will aid in holistic understanding of the GDL.This study aims to provide greater insight into the ICR and the development of alternative GDL coated MPLs to improve interfacial characteristics. In addition, it is intended to explore novel materials for MPL coatings such as carbon nanotubes and graphene. The development of new combinations of materials and different designs for the GDL is aiming at reducing the interfacial contact resistance, increase electrical conductivity, thus improving the overall performance of PEMFC operation. The objective of this project is divided into 3 main parts:Accurately quantify the interfacial contact resistance between GDL and the flow field plate and between the GDL and the catalyst layer.Optimise the double-sided MPL coated GDL by examining characterisation and holistic performance on PEMFC.Optimise the use of novel materials for use in the double-sided MPL coated GDL by characterisations and overall PEMFC performance.

燃料电池是将反应的化学能直接转化为电能的电化学装置。质子交换膜燃料电池（PEMFC）是特别重要的领域。这是因为它们非常通用。例如，它们可用于便携式能源、固定能源生产和运输等应用。此外，它们可能在未来的“氢经济”中发挥重要作用。这包括促进减少温室气体排放和减少对化石燃料技术的依赖。气体扩散层（GDL）是质子交换膜燃料电池（PEMFC）的关键部件。GDL在PEMFC运行中的作用是多方面的。它提供了一种介质，反应气体可以通过该介质扩散，同时允许去除过量的液态水。GDL还促进了通过PEMFC的热量和电子传递。此外，它还为精细的催化剂层和膜提供机械支撑。GDL是催化剂和双极板之间的重要介质，这导致了对GDL性能的大量研究。尽管如此，GDL仍然是PEMFC中相当大的操作损耗的区域，特别是欧姆损耗。这些损失在燃料电池内部件之间的界面接触处变得更加重要;这对于GDL尤其重要，因为它位于双极板和催化剂层之间。在接触界面处的电损耗，例如在GDL和双极板之间以及在GDL和催化剂层之间的电损耗显著高于单个部件的体积损耗。为了增强GDL在与催化剂层的界面接触处的性质，常规地施加微孔层（MPL）。通常，MPL由与PTFE和粘合剂混合的碳颗粒组成。MPL已被证明改善了催化剂层界面处GDL的整体性能，包括电接触的改善。本研究的主要目的是通过应用双面MPL涂层GDL来降低界面接触电阻（ICR），从而提高PEMFC的性能。这将通过用双面MPL涂覆GDL来实现。一个MPL将面向催化剂层，另一个将面向双极板。降低质子交换膜燃料电池的欧姆损耗一直是许多研究小组关注的焦点。然而，通过使用双面MPL涂覆的GDL减少ICR来减少欧姆损耗仍然没有完全理解。特别注意将支付给非原位表征测量，因为这些将有助于GDL.This研究的目的是提供更深入的了解ICR和替代GDL涂层MPLS的发展，以改善界面特性的整体理解。此外，还打算探索用于MPL涂层的新型材料，如碳纳米管和石墨烯。开发新的材料组合和不同的GDL设计旨在降低界面接触电阻，增加电导率，从而提高PEMFC运行的整体性能。本项目的目标分为三个主要部分：准确量化GDL与流场板之间以及GDL与催化剂层之间的界面接触阻力;通过考察表征和PEMFC的整体性能来优化双面MPL涂层GDL;通过表征和整体性能来优化用于双面MPL涂层GDL的新型材料。