Periodic Reporting for period 1 - IMMORTAL (IMproved lifetiMe stacks fOR heavy duty Trucks through ultrA-durabLe components)
Reporting period: 2021-01-01 to 2022-06-30
IMMORTAL has the overall aim of developing exceptionally durable and high power density membrane electrode assemblies (MEAs) specific to heavy-duty truck operation with designs satisfying the operational (beginning of life power density of 1.2 W/cm2 at 0.675 V) and durability (30,000 hours) targets of the call.
IMMORTAL began in the middle of the delta-covid wave in January 2021, which restricted on-site working and closed some laboratories, and delayed deliveries from suppliers. This led to a slower-than-usual commencement of the experimental work. Despite this, IMMORTAL has made excellent progress in all work packages (WP), has delivered fifteen of the seventeen deliverables due in the first reporting period (RP1) and achieved the milestones due at M12 and M15.
WP2 focuses on the evaluation and prediction of real-life durability of the heavy-duty specific MEAs developed in IMMORTAL. Since testing over the targeted 30,000 h of lifetime is beyond the scope of the project, WP2 concentrates on the development and conduction of load profile tests (LPTs) and accelerated stress tests (ASTs) and correlation of the resulting ageing observed. In RP1, an initial set of ASTs were defined for single cells and a novel AST procedure proposed for use with short stacks. An initial LPT was developed. These ASTs and LPTs were applied to the benchmark MEA, in single cells and short stacks. End-of-test analyses of the MEAs were conducted using a range of techniques to determine the predominant ageing mechanism. First empirical correlations were drawn between the experimentally observed degradation rates on AST and LPT. However, from that LPT, the preliminary lifetime prediction yields a durability for the benchmark MEA that is significantly shorter than the target 30,000 hours, which underlines the importance of both the materials development efforts in WP3-WP5 and the test protocol development in WP2 using the input from WP6.
WP3 is dedicated to the development of active and stable anode and cathode catalysts and to new and stable supports. A wide library of rare earth alloys were developed and their evaluation led to the identification of a PtGd/C rare earth alloy with similar activity but improved stability compared to benchmark PtNi/C catalysts. This is a promising result towards the final performance and durability targets of this project. Larger scale preparations enabled validation in 50 cm2 single cells. Significant improvements were made towards the controlling catalyst particle size distribution and degree of alloying. Further PtNi/C and PtCo/C alloy variants were also improved. High resistance of the carbon support to electrochemical corrosion is essential, and a more stable carbon support than the benchmark was identified. This support was catalysed at 100 g batch size and transferred to WP5 for further validation in layers. In addition, synthesis of functionalised carbon supports was demonstrated and valuable knowledge was developed towards the parameters that lead to the desired type of N-functionality on different carbon supports.
The objectives of WP4 are to develop an exceptionally durable membrane specific to heavy-duty truck application. The ionomer but also the reinforcement and the component used as radical scavenger/hydrogen peroxide decomposition catalyst, are all of crucial importance, as well as the membrane construction and membrane thickness. Several ionomers have been characterised for their properties most relevant for long-term operation, and the results used to select an ionomer that best satisfies durability and performance requirements. The formulation and processing of thermostable nanofibre reinforcements have been further improved. The first heavy-duty-specific membrane has been fabricated and transferred to WP5 for the first generation of MEAs to be tested in single cells and short stacks in WP2.
WP5 on MEA development is central to IMMORTAL. More than 100 IMMORTAL baseline MEAs were produced for stack manufacture and testing in the first months of the project. Since then, WP5 has made excellent progress towards reaching the project target through integration of WP3 catalysts into cathode catalyst layers, and by assessing formulation of the catalyst layers. This has delivered significant benefits in performance, which has resulted in a 20% increase in power density at 0.675 V compared with the benchmark MEA, and has brought the performance to within 6% of the project power density target at 1.8 A/cm2. Significant advances have also been made in reducing the platinum loading. Design down-selection and material preparation for the first heavy-duty specific MEA design are complete, in preparation for manufacture of MEA parts.
WP6 aims at validating the project results for heavy-duty fuel cell truck application. In RP1, the focus was on collecting field data to define load frequency distribution. Several real heavy-duty commercial vehicle missions were selected and simulations of heavy-duty trucks were conducted to produce load profiles. Selection criteria were defined and used to distinguish the most appropriate cycles for further use in WP2 and the refinement of stack testing protocols.
In WP7, framed by an internal protocol on dissemination and knowledge management, IMMORTAL has conducted activities to communicate on, and disseminate, project results, including through the implementation of a project website, use of visual identity tools, by conference presentations, a review article, project brochure, and press releases. An annual newsletter is in preparation.
WP2 focuses on the evaluation and prediction of real-life durability of the heavy-duty specific MEAs developed in IMMORTAL. Since testing over the targeted 30,000 h of lifetime is beyond the scope of the project, WP2 concentrates on the development and conduction of load profile tests (LPTs) and accelerated stress tests (ASTs) and correlation of the resulting ageing observed. In RP1, an initial set of ASTs were defined for single cells and a novel AST procedure proposed for use with short stacks. An initial LPT was developed. These ASTs and LPTs were applied to the benchmark MEA, in single cells and short stacks. End-of-test analyses of the MEAs were conducted using a range of techniques to determine the predominant ageing mechanism. First empirical correlations were drawn between the experimentally observed degradation rates on AST and LPT. However, from that LPT, the preliminary lifetime prediction yields a durability for the benchmark MEA that is significantly shorter than the target 30,000 hours, which underlines the importance of both the materials development efforts in WP3-WP5 and the test protocol development in WP2 using the input from WP6.
WP3 is dedicated to the development of active and stable anode and cathode catalysts and to new and stable supports. A wide library of rare earth alloys were developed and their evaluation led to the identification of a PtGd/C rare earth alloy with similar activity but improved stability compared to benchmark PtNi/C catalysts. This is a promising result towards the final performance and durability targets of this project. Larger scale preparations enabled validation in 50 cm2 single cells. Significant improvements were made towards the controlling catalyst particle size distribution and degree of alloying. Further PtNi/C and PtCo/C alloy variants were also improved. High resistance of the carbon support to electrochemical corrosion is essential, and a more stable carbon support than the benchmark was identified. This support was catalysed at 100 g batch size and transferred to WP5 for further validation in layers. In addition, synthesis of functionalised carbon supports was demonstrated and valuable knowledge was developed towards the parameters that lead to the desired type of N-functionality on different carbon supports.
The objectives of WP4 are to develop an exceptionally durable membrane specific to heavy-duty truck application. The ionomer but also the reinforcement and the component used as radical scavenger/hydrogen peroxide decomposition catalyst, are all of crucial importance, as well as the membrane construction and membrane thickness. Several ionomers have been characterised for their properties most relevant for long-term operation, and the results used to select an ionomer that best satisfies durability and performance requirements. The formulation and processing of thermostable nanofibre reinforcements have been further improved. The first heavy-duty-specific membrane has been fabricated and transferred to WP5 for the first generation of MEAs to be tested in single cells and short stacks in WP2.
WP5 on MEA development is central to IMMORTAL. More than 100 IMMORTAL baseline MEAs were produced for stack manufacture and testing in the first months of the project. Since then, WP5 has made excellent progress towards reaching the project target through integration of WP3 catalysts into cathode catalyst layers, and by assessing formulation of the catalyst layers. This has delivered significant benefits in performance, which has resulted in a 20% increase in power density at 0.675 V compared with the benchmark MEA, and has brought the performance to within 6% of the project power density target at 1.8 A/cm2. Significant advances have also been made in reducing the platinum loading. Design down-selection and material preparation for the first heavy-duty specific MEA design are complete, in preparation for manufacture of MEA parts.
WP6 aims at validating the project results for heavy-duty fuel cell truck application. In RP1, the focus was on collecting field data to define load frequency distribution. Several real heavy-duty commercial vehicle missions were selected and simulations of heavy-duty trucks were conducted to produce load profiles. Selection criteria were defined and used to distinguish the most appropriate cycles for further use in WP2 and the refinement of stack testing protocols.
In WP7, framed by an internal protocol on dissemination and knowledge management, IMMORTAL has conducted activities to communicate on, and disseminate, project results, including through the implementation of a project website, use of visual identity tools, by conference presentations, a review article, project brochure, and press releases. An annual newsletter is in preparation.
The understanding generated and the clear development pathways allow confidence that the project targets will be fully achieved by the project end.