Periodic Reporting for period 1 - FURTHER-FC (Further Understanding Related to Transport limitations at High current density towards future ElectRodes for Fuel Cells)
Période du rapport: 2020-01-01 au 2021-06-30
The FURTHER-FC project aims at developing an innovative route towards a better understanding of performance limitations inside Proton Exchange Membrane Fuel Cells (PEMFC), focusing on the Cathode Catalyst Layer (CCL) as the major bottleneck for performance, cost and durability for future high performing low-Pt loaded PEMFC for automotive application.
Based on the active involvment of renowned actors, the project combines original and/or most advanced methods with intensive fundamental characterizations coupled with advanced models on CCL of various compositions/structures to conclude on transport and electrochemical issues.
The main objectives are:
• describe the CCL structure, transport properties and mechanisms at its different scales
• characterize local conditions in the CCL during operation
• establish the link between structure and properties of CCL, local conditions during operation, and performance
• propose and validate CCL with improved catalyst efficiency and durability
Based on the active involvment of renowned actors, the project combines original and/or most advanced methods with intensive fundamental characterizations coupled with advanced models on CCL of various compositions/structures to conclude on transport and electrochemical issues.
The main objectives are:
• describe the CCL structure, transport properties and mechanisms at its different scales
• characterize local conditions in the CCL during operation
• establish the link between structure and properties of CCL, local conditions during operation, and performance
• propose and validate CCL with improved catalyst efficiency and durability
RP1 has consisted mainly in defining the materials and test conditions between the partners, manufacturing and supplying first components to validate and/or start the different characterizations Modelling activity has started based on the preliminary experimental results.
Specifications and manufacturing:
• Selection and purchase of materials for reference and customized Membrane Electrode Assemblies (MEA)
• Manufacturing and supply of reference MEA
• Definition of test protocols and conditions to check performance and durability in technical and differential single cells; modifications of the cells to allow more relevant comparison of results between the partners
Ex-situ characterization of materials:
• Data collection for the Micro Porous Layer (MPL) and the substrate of the reference GDL; measurement of their 3D structures for modelling
• Characterization of reference catalyst powder: catalyst on or inside the carbon support
• Progress on thin ionomer film: swelling, proton conductivity, O2 transport limitation
• Progress on CCL: porosity, catalyst and carbon support distribution, ionomer distribution, 3D structure, effective properties (electric, proton and thermal conductivities)
In-operando characterization of materials:
• Test of reference MEA between the partners: validation of electrochemical properties in technical cell, on-going comparison of analysis in the differential cell
• First operando thermography experiments with the reference MEA: increase of the local membrane temperature with the increase of the current density
• Preliminary measurements of Operando SANS have been conducted to quantify the local RH and water content in the CCL
Modelling:
• Direct Numerical Simulation (DNS) and Pore Network Modelling (PNM) have started on the 3D MPL structure, first effective properties have been derived
• Lattice-Boltzmann Modelling (LBM) (sub-µm scale) is under development based on the first CCL 3D images; multi-component diffusion and conversion of components on the platinum particle surface have been implemented
• DNS of the CCL (agglomerate scale) has started coupling charge, mass, heat transfers and local electrochemistry at the Pt/C scale
• Based on the DNS formal upscaling has started to evaluate CCL relevant transport equations at the ‘average’ scale
• An ‘average’ model of the differential cell has been implemented, the validation has started based on the electrochemical characterization of the reference MEA
Specifications and manufacturing:
• Selection and purchase of materials for reference and customized Membrane Electrode Assemblies (MEA)
• Manufacturing and supply of reference MEA
• Definition of test protocols and conditions to check performance and durability in technical and differential single cells; modifications of the cells to allow more relevant comparison of results between the partners
Ex-situ characterization of materials:
• Data collection for the Micro Porous Layer (MPL) and the substrate of the reference GDL; measurement of their 3D structures for modelling
• Characterization of reference catalyst powder: catalyst on or inside the carbon support
• Progress on thin ionomer film: swelling, proton conductivity, O2 transport limitation
• Progress on CCL: porosity, catalyst and carbon support distribution, ionomer distribution, 3D structure, effective properties (electric, proton and thermal conductivities)
In-operando characterization of materials:
• Test of reference MEA between the partners: validation of electrochemical properties in technical cell, on-going comparison of analysis in the differential cell
• First operando thermography experiments with the reference MEA: increase of the local membrane temperature with the increase of the current density
• Preliminary measurements of Operando SANS have been conducted to quantify the local RH and water content in the CCL
Modelling:
• Direct Numerical Simulation (DNS) and Pore Network Modelling (PNM) have started on the 3D MPL structure, first effective properties have been derived
• Lattice-Boltzmann Modelling (LBM) (sub-µm scale) is under development based on the first CCL 3D images; multi-component diffusion and conversion of components on the platinum particle surface have been implemented
• DNS of the CCL (agglomerate scale) has started coupling charge, mass, heat transfers and local electrochemistry at the Pt/C scale
• Based on the DNS formal upscaling has started to evaluate CCL relevant transport equations at the ‘average’ scale
• An ‘average’ model of the differential cell has been implemented, the validation has started based on the electrochemical characterization of the reference MEA
Progress beyond SoA and expected results
• Material properties
o Ionomer: swelling, proton and electric properties, oxygen transport
o Catalyst: distribution on the carbon support
• CCL properties
o Distribution of ionomer, catalyst, carbon support, pores
o Effective properties: porosity, proton and electron transport, proton activity, wettability
o Scanning Thermal Microscopy applied to fuel cell materials like MEAs
o Exchange current densities for ORR and HOR on thin electrodes
• In-operando characterization
o Water content and relative humidity in the CCL
o Evaluation of the temperature of the membrane
• Modelling
o Improved models at the different scales (DNS, LBM, PNM) based on microstructure of the CCL
o Upscaling of transport mechanisms between the different scales
o Validated multiscale cell model to quantify the contribution of all mechanisms to the overall performance limitation
• Performance limitations
o Improved quantification of O2 transport losses at different scales based on microstructure resolved models
o Better separation of anodic and cathodic processes
o Characterization of ultra-low loading MEAs
o First indications of additional rate limiting step at the cathode by adsorption processes on catalyst surface
o In situ catalyst activity measurement as a function of potential using the equilibrated Tafel plot method, insight on the impact of oxide coverage and of Pt-ionomer interaction
The FURTHER-FC project constitutes a step forward towards a better understanding on performance limitations in PEMFC. The knowledge could be of use for other technologies such as PEMWE, AEMFC, or even solar cells.
The project will have positive impacts for the partners:
• CEA:
o Better understand transport limitations and material improvements
o Improved analysis tools and methods
o Develop new skills and knowhow that could be used for other technologies
o International scientific recognition
• DLR:
o Development of advanced physical models for better understanding the mechanisms and high predictivity for future simulation-based fuel cell design and optimization
o Improved setup for differential cell tests for deep analysis of transport and catalytic properties
• ICL
o Better understanding of CCLs could reduce the PGM requirements for PEMFCs, thus reducing the environmental and social impact of PEMFCs due to mining
o Develop better electrocatalyst testing techniques and skills
• IEM:
o Team increased visibility and notoriety in the international community concerned by in situ spectroscopy and operando characterization of electrochemical devices
o Increased number of collaborations in various areas where there is a need to measure temperature by contactless techniques (e.g. transistor)
• PSI:
o The integrated approach of MEA performance analysis, including a variety of advanced in situ characterization techniques and multipartner scientific discussions on the combined analysis, is expected to result in a significant impact in the way MEAs are characterized in the future.
• UES:
o Help in teaching students in the fuel cell technology and raise the attention to possible future scientists
o Advanced sample preparation and elaborate atomic force microscopy techniques used for fuel cell materials can be used in future developments.
• TME:
o Current 2nd generation Mirai is using a special mesoporous carbon which is as expensive as Platinum. Better understanding of mass transport will allow to better design this type of material in the future
• CHEM:
o Chemours continues to innovate on chemistries for improved oxygen permeability and/or proton transport at elevated operating temperatures. The knowledge gathered in Further-FC may contribute to generate the ideal combination of oxygen permeability, proton and water transport, and physical characteristics (i.e. well-formed electrodes) for CCLs.
• INPT:
o Improved modelling and upscaling in PEMFC
• Material properties
o Ionomer: swelling, proton and electric properties, oxygen transport
o Catalyst: distribution on the carbon support
• CCL properties
o Distribution of ionomer, catalyst, carbon support, pores
o Effective properties: porosity, proton and electron transport, proton activity, wettability
o Scanning Thermal Microscopy applied to fuel cell materials like MEAs
o Exchange current densities for ORR and HOR on thin electrodes
• In-operando characterization
o Water content and relative humidity in the CCL
o Evaluation of the temperature of the membrane
• Modelling
o Improved models at the different scales (DNS, LBM, PNM) based on microstructure of the CCL
o Upscaling of transport mechanisms between the different scales
o Validated multiscale cell model to quantify the contribution of all mechanisms to the overall performance limitation
• Performance limitations
o Improved quantification of O2 transport losses at different scales based on microstructure resolved models
o Better separation of anodic and cathodic processes
o Characterization of ultra-low loading MEAs
o First indications of additional rate limiting step at the cathode by adsorption processes on catalyst surface
o In situ catalyst activity measurement as a function of potential using the equilibrated Tafel plot method, insight on the impact of oxide coverage and of Pt-ionomer interaction
The FURTHER-FC project constitutes a step forward towards a better understanding on performance limitations in PEMFC. The knowledge could be of use for other technologies such as PEMWE, AEMFC, or even solar cells.
The project will have positive impacts for the partners:
• CEA:
o Better understand transport limitations and material improvements
o Improved analysis tools and methods
o Develop new skills and knowhow that could be used for other technologies
o International scientific recognition
• DLR:
o Development of advanced physical models for better understanding the mechanisms and high predictivity for future simulation-based fuel cell design and optimization
o Improved setup for differential cell tests for deep analysis of transport and catalytic properties
• ICL
o Better understanding of CCLs could reduce the PGM requirements for PEMFCs, thus reducing the environmental and social impact of PEMFCs due to mining
o Develop better electrocatalyst testing techniques and skills
• IEM:
o Team increased visibility and notoriety in the international community concerned by in situ spectroscopy and operando characterization of electrochemical devices
o Increased number of collaborations in various areas where there is a need to measure temperature by contactless techniques (e.g. transistor)
• PSI:
o The integrated approach of MEA performance analysis, including a variety of advanced in situ characterization techniques and multipartner scientific discussions on the combined analysis, is expected to result in a significant impact in the way MEAs are characterized in the future.
• UES:
o Help in teaching students in the fuel cell technology and raise the attention to possible future scientists
o Advanced sample preparation and elaborate atomic force microscopy techniques used for fuel cell materials can be used in future developments.
• TME:
o Current 2nd generation Mirai is using a special mesoporous carbon which is as expensive as Platinum. Better understanding of mass transport will allow to better design this type of material in the future
• CHEM:
o Chemours continues to innovate on chemistries for improved oxygen permeability and/or proton transport at elevated operating temperatures. The knowledge gathered in Further-FC may contribute to generate the ideal combination of oxygen permeability, proton and water transport, and physical characteristics (i.e. well-formed electrodes) for CCLs.
• INPT:
o Improved modelling and upscaling in PEMFC