Experimental and theoretical investigations of transport processes in polymer electrolyte fuel cells

加拿大目前的化石燃料运输部门消耗了我们一次能源的近30%。聚合物电解液燃料电池(PEFC)和电池为替代目前的运输能源系统提供了可行的替代方案。利用可再生能源的电力，在聚合物电解质电解槽(PEE)中分解水产生的氢气，可以用于PEFC为车辆提供动力。PEFC只产生水蒸气，从而消除污染和温室气体排放。PEFC汽车展示了客户期望的所有属性，如快速启动和加油、续航里程和耐用性。提高PEE和PEFC汽车市场渗透率的先决条件是降低生产成本以及改进性能和耐用性。*为了将PEFC和PEFC的成本降低到商业化目标，即分别为30美元/千瓦和300美元/千瓦(2020年美国能源部目标)，有必要改善电极中的质量传输，以实现更高的功率密度运行和更低成本的催化剂的使用。由于材料和物理现象的复杂性，PEFC和PEE的分析和设计需要数值模拟。燃料电池和电解槽的宏观数值模拟已经取得了显著的进展。然而，这些模型不能解释PEFC和PEE中多孔复合材料的微观特征如何影响质量传输特性和反应。应结合统计分析、重建和模拟的纳米尺度成像来解释这些影响。在高电流密度下，液态水在电极中的积累也减少了向反应现场的传输，从而限制了燃料电池的最大功率。通过使用喷墨打印等微制造技术设计更好的传输层，可以最大限度地减少水分积累。上述问题、降解和材料研究对PEFC和PEE至关重要。*拟议的发现赠款计划旨在开发：a)微尺度统计分析、重建、数值模型和非现场实验工具，以研究电极微结构对传输特性和水积累的影响；以及，b)旨在最大限度减少水积累的新型燃料电池结构。重点将放在PEFC上，然而，由于物理过程的封闭性，数值和实验工具也适用于PEE。*新的数值模型和结构旨在设计具有更高催化剂利用率和最大功率密度的电极，从而能够导致更便宜和更好的PEFC。这项研究将通过开发基础知识、新工具和培训HQP来保持加拿大在燃料电池领域的领导地位，从而为加拿大经济做出贡献。我的软件已经在加拿大的工业中使用。**

Canada's current fossil fuelled transportation sector consumes nearly 30% of our primary energy. Polymer electrolyte fuel cells (PEFCs) and batteries present viable alternatives to replace the current transportation energy system. Hydrogen, produced by water splitting in a polymer electrolyte electrolyzer (PEE) using electricity from renewable energy sources, could be used in PEFCs to power a vehicle. PEFCs produce only water vapor thereby eliminating pollution and greenhouse gas emissions. PEFC vehicles have demonstrated all the attributes that customers expect such as quick start-up and refuelling, long range, and durability. Prerequisites for an increase in market penetration of PEE, and PEFC vehicles, are production cost reductions as well as performance and durability improvements.***In order to reduce the cost of PEFCs and PEEs to commercialization targets, i.e., $30/kW and $300/kW respectively (2020 U.S. Department of Energy targets), it is necessary to improve mass transport in the electrode in order to enable higher power density operation and the use of less precious catalysts. Due to the complex materials and physical phenomena, numerical modelling is required for PEFC and PEE analysis and design.***Remarkable progress has been achieved in macroscale numerical modelling of fuel cells and electrolyzers. These models however cannot account for how microscopic features in the porous composite materials in PEFCs and PEEs affect mass transport properties and reactions. Nanometer scale imaging combined with statistical analysis, reconstruction, and simulation should be used to account for these effects. At high current density, liquid water accumulation in the electrode also reduces transport to the reaction site, thereby limiting the fuel cell maximum power. Water accumulation can be minimized by designing better transport layers using micro-fabrication techniques such as inkjet printing. The issues above, degradation, and material research are critical to PEFCs and PEEs.***The proposed Discovery grant program aims at developing: a) micro-scale statistical analysis, reconstruction, and numerical models, and ex-situ experimental tools to study the effect of electrode micro-structures on transport properties and water accumulation; and, b) novel fuel cell architectures that aim at minimizing water accumulation. The focus will be in PEFCs, however, due to the closeness of physical processes, the numerical and experimental tools are also applicable to PEEs.***The new numerical models and architectures aim at designing electrodes with increased catalyst utilization and maximum power density which can lead to cheaper and better performing PEFCs. This research will contribute to the Canadian economy by developing fundamental understanding, novel tools, and training HQP to maintain Canada's leadership in fuel cells. My software is already in use at Canadian industries.**