Topical Meeting on Electrocatalysis on Fuel Cells 2017
November 15, 2017
Hotel Radisson Blu, Berlin
Room Aquamarin , Karl-Liebknecht-Str. 3, 10178 Berlin
The Topical Meeting on Electrocatalysis on Fuel Cells, organised by the AFC TCP focused on presenting and summarising the spearhead of the international scientific activities on catalyst research and development for PEM fuel cells for vehicles and the electrolysis. Building up on the presentations and discussions the meeting had the special task to point out the future perspectives and chances of these technologies.
In the first part of the meeting internationally renowned catalyst experts from US, Japan, Germany and Switzerland gave insights into catalyst research for fuel cells. The talks concentrated on the recent progress on the key issues like cost reduction, increased durability and improved power density from different point of views. In the second part the AFC TCP experts contributed with talks on current topics.
Anusorn Kongkanand is a project leader responsible for advanced catalysts and diagnostics research and development at General Motors. Through collaboration with industrial suppliers and academia, he leads GM effort on to enable the reduction of costly Pt use in proton exchange membrane fuel cells (PEMFCs). He also acts as the principal investigator on a US Department-of-Energy project on high-performance fuel cell electrode. He has published over 40 articles and reviews in the area of energy conversion technologies, accumulating >3000 citations. He holds 18 approved or pending patents.
Fuel cell electric vehicles with about 35 g of Pt are now on the road, and next-generation FCEVs are expected to use about 10-20 g of Pt-group metals (PGM). These are significant accomplishments and encouraging progress toward commercializing this sustainable transportation technology. However, considering commercial factors as well as promising catalyst technologies early in the pipeline, a long-term PGM target is warranted at a level comparable to that used in automotive catalytic convertors (~5 gPGM). Progress in Pt-based catalysts in recent years has been due to alloy optimization resulting in notable activity gains, but opportunities remain to achieve better Pt surface area (ECSA) and alloy stability over operating life. Further enhancement of oxygen reduction reaction activity must be achieved to enable the long-term target of 5 gPGM per vehicle. In addition to these structure and kinetics considerations, fundamental understanding of the origin of the local transport resistance is needed in order to optimally engineer the nanostructure near the catalyst active surfaces. Development of ionomer and carbon support structures specifically designed for this purpose is a promising research direction, as encouraging early data exists. Last, an establishment of public policy is required to develop a resource management system where PGM-containing products are collected back from customers. Judging from steady progress made in past decades, we are optimistic that the concerted efforts of materials developers and electrode designers can resolve these issues, enabling fuel cell vehicles that are affordable for the mass market.
Prof. Shigenori Mitsushima is heading the Chemical Energy Laboratory of the Green Hydrogen Research Center and the Research unit for chemistry of hydrogen energy conversion of the Institute of Advanced Sciences in Yokohama National University (YNU). He received Master’s degree from YNU in 1989, and he joined Hitachi, Ltd. He received Doctor in Engineering degree from YNU in 1998 with development of molten carbonate fuel cells in Hitachi, Ltd. In 2000, he joined YNU as a research associate, and got full professor in 2011 through associate professor from 2006. He has longtime experience for research on fuel cell technology, industrial electrolysis, and hydrogen energy from material to systems as an academic and an industrial engineer. He is a vice president of the Hydrogen Energy System Society of Japan, and an associate editor for Electrocatalysis, a Springer journal. Recent research topics are materials and membrane electrolyzer system of hydrogenation of toluene with water decomposition for energy carrier synthesis, nickel based durable anode of alkaline water electrolysis to connect renewable energies, and non-precious metal oxide electrocatalyst for oxygen reduction reaction of polymer electrolyte fuel cells (PEFCs).
Polymer electrolyte water electrolysis is under developing as a key technology of power to gas. Understanding of electrocatalyst degradation mechanism and development of active and durable electrode is ongoing, while alkaline water electrolysis is considered as well developed technology. Power to liquid technology is also essential to long term storage and ship transportation. Membrane electrolysis for hydrogenation of toluene with water decomposition is successfully demonstrated as energy carrier synthesis using renewable electricity.
In February 2011, Professor Thomas J. Schmidt became Chair of Electrochemistry at ETH Zurich in February 2011, combined with the appointment as Head of the Electrochemistry Laboratory at Paul Scherrer Institute in Villigen, Switzerland. Since 2014 Prof. Schmidt is also Director of the Swiss Competence Center for Energy Research (SCCER) Heat & Electricity Storage.
Thomas Schmidt received his University Diploma in Chemistry from the University of Ulm/Germany in 1996 and his PhD in Chemistry from the same University in 2000. That same year he joined the group of P.N. Ross and N.M. Markovic at Lawrence Berkeley National Laboratory as a Chemist Postdoctoral Fellow. During this period, he intensively studied the fundamentals of electrocatalysis of fuel cell reactions. Since fall 2002, he was working in the industrial development of high temperature membrane electrode assemblies and its components (membranes, catalysts, electrodes) using polybenzimidazole based membranes at BASF Fuel Cell GmbH. During these eight years in industries, Dr. Schmidt led the high-temperature MEA R&D activities as Director R&D and helped to successfully commercialize the BASF Fuel Cell Celtec® MEAs. Currently, Prof. Schmidt is Associate Editor of the Journal of the Electrochemcial Society. In fall 2010, he received the Charles W. Tobias Young Investigator Award from the Electrochemical Society. He was awarded the Otto-Monsted Visiting Professorship at the Technical University of Denmark (Lyngby) in 2013.
The main issues for the durability of electrocatalysts in PEFCs are typically related to transient operation conditions like start/stop operation, extensive voltage cycling (both cathode) and gross hydrogen starvation (anode). In order to improve corrosion stability of supports for cathodes, the key strategies include using supporless, purely metallic systems (e.g., metallic aerogels) or transition metal oxide supported Pt. Aerogels have been shown to be basically unaffected by start/stop and voltage cycling. Oxide supported catalysts, specifically using transition metal oxides with flat band potentials at around 0.9 to 1V could be shown to protect the Pt nanoparticles from Ostwald due to electrochemical transistor switching. In addition, under gross fuel starvation, aerogel anodes, even when using low loadings demonstrate extremely good stability with no changes on ine both the hydrogen oxidation kinetics and mass transport resistances in the
Professor Gasteiger received his PhD in Chemical Engineering from UC Berkeley in 1993, studying the electrocatalysis of methanol oxidation. After 9 years of academic research on electrocatalysis and heterogeneous gas-phase catalysis at UC Berkeley, the Lawrence Berkeley Laboratory, and at Ulm University, he spent 10 years working in industry. From 1998 to 2007, Professor Gasteiger was leading the fuel cell stack materials development for GM/Opel’s H2powered fuel cell vehicles (Rochester, NY, USA). In 2007 he joined Acta S.p.A. (Italy) as Director of Catalyst Technology, developing catalysts and electrodes for alkaline (membrane) fuel cells and electrolyzers. In January 2009 he took an assignment as Visiting Professor at MIT, working on lithium-air batteries. At TUM he is working as Full Professor in Technical Electrochemistry in the areas of electrocatalysis and batteries. He published 72 papers (h-index 42; 8600 citations) in refereed journals as well as 13 book chapters, and has 29 patents/patent applications.
The automotive target of <0.1gPt/kW can in principle be met by use of Pt-alloy nanoparticle cathode catalysts and stack materials designed for high current densities in order to minimize mass transport related voltage losses. For cathode catalysts, the distribution of nanoparticles on the support has a significant impact on high-current density performance. Optimized design of gas diffusion layers (substrates and microporous layers) are also critical to minimize mass transport losses and to enable high-current density performance.
Dr. Ahluwalia is a Senior Engineer in Nuclear Engineering Division at Argonne National Laboratory. He is a Principal Investigator of several DOE-EERE funded projects on fuel cell system analysis, fuel cell performance and durability (FC-PAD and ElectroCat), and system analysis of on-board hydrogen storage systems.
The performance and durability of low-PGM Pt-transition metal (Co or Ni) alloy cathode catalysts, supported on high surface-area carbon with tailored pore size distribution, have been investigated for use in an 80-kWe automotive polymer electrolyte fuel cell (PEFC) system under operating conditions required to meet the heat rejection constraint: Q/DT = 1.45 kW/°C, where Q is the stack heat load and Delta T is the difference in coolant exit and ambient (40°C) temperatures. These alloy catalysts have more than double the ORR (oxygen reduction reaction) mass activity of Pt/C catalysts that have been stabilized by heat-treatment to grow the nanoparticles to similar size (4-5 nm) as in the de-alloyed PtNi/C. System analysis indicates that PEFC stacks with PtCo/C cathode catalysts, 0.125 mg/cm2 total Pt loading on cathode and anode, and 14-micro m chemically-stabilized, mechanically reinforced PFSA membrane can achieve >1000 mW/cm2 power density at Q/Delta T relevant conditions. Achieving this level of performance requires that the stack be operated at low cathode stoichiometry (1.5), moderate stack inlet pressure (2.5-3.0 atm), elevated temperature (>95°C coolant exit temperature), and relatively dry air at cathode inlet (70-78°C dew point temperature). We project that a PEFC system with the alloy cathode catalyst will cost <$45/kW at high volume manufacturing (500,000 units/year) and the required Pt content will be <0.113 gPt/kWe stack power. The projected stack power density and Pt content exceed the targets set by USDOE Fuel Cell Tech Team.
The transition metal (TM) in the alloy catalyst is thermodynamically unstable at fuel cell operating potentials. Accelerated stress tests (AST), designed to characterize catalyst degradation under cyclic potentials, show extensive leaching of Ni out of the d-PtNi/C catalyst into the ionomer in the electrode and the adjoining membrane, and relaxation of strain (d-spacing) that is responsible for high ORR activity. In spite of >90% Ni loss, there is only a 10% decrease in the measured ORR specific activity, which remains higher than 1000 micro A/cm2Pt. We also observe enhanced oxygen mass transport losses with d-PtNi/C catalyst degradation, and these losses correlate with the measured decrease in the electrochemically active surface area (ECSA). We project that the goal of limiting degradation in stack rated power to <10% over the vehicle lifetime can be met by restricting the ECSA loss to <40%. The AST data shows that ECSA loss depends on the potential waveform and can be contained to <40% by controlling the upper potential limit and the scan rate.
The foregoing conclusions are based on laboratory data obtained in subscale integral and differential cells under simulated conditions, and need to be validated on full-area stacks in PEFC systems operated under actual field conditions.
Göran Lindbergh has both an MSc (1985) and PhD (1991) in Chemical Engineering from KTH Royal Institute of Technology, Stockholm, Sweden. He is Professor in Electrochemical Process and System Engineering at KTH, since 2003, and since 2005 heading the Department of Chemical Engineering. He is also a member of The Royal Swedish Academy of Engineering Sciences (IVA). He has more than 170 published journal papers. His research is directed towards batteries, fuel cells and electrolysis within the field of electrochemical engineering. Implementation of batteries and fuel cells in the transportation sector is a common theme in the research. He has worked on Proton Exchange Membrane Fuels Cells (PEMFC) for more than 20 years, often in close collaboration with industry. These activities include mathematical modelling, electrode-, cell- and system optimisation, electrochemical characterisation of new catalysts and membrane materials, and durability and lifetime issues of fuel cells. He also has experience from working with alternative fuels and the influence of impurities on fuel cell performance.
A major hurdle for the large-scale commercialization of PEM fuel cell is its high cost, which is primarily due to the use of precious metals as the electrocatalysts. Finding inexpensive and stable material to reduce or replace the precious metals has been the ultimate goal in the fuel cell research for decades. Recently, many advancements have been made world-wide, with some remarkable catalyst performance reported. In this presentation, I will discuss some recent concepts and results in rational design and synthesis of ultralow Pt and platinum metal group (PGM) free catalysts, as well as their implication to PEM fuel cell performances. Novel electrode architectures with improved mass/charge transfers will also be discussed.
Dr. Lior Elbaz has a BSc, MSc and PhD in chemical engineering, all from the Ben-Gurion University, Israel. During his graduate studies, he became an expert in electrochemistry and electrocatalysis. He used his expertise to develop tumor targeting drugs, solar cells and fuel cells. After finishing his PhD, he joined the MPA-11 group, at the Materials Physics & Applications Division at the Los Alamos National Laboratory, a world leader in the development of fuel cell technology, where he developed new catalysts and advanced materials for fuel cells, in order to reduce fuel cells price and increase their durability. After almost four years at Los Alamos, Lior came back to Israel to take a position at the Department of Chemistry, Bar-Ilan University. After returning to Israel, Lior decided to found the Israeli fuel cells consortium, composed of 12 leading Israeli labs and generously funded by the Israeli prime minister’s office.
One of the most interesting and challenging reactions in low temperature fuel cells today is oxygen reduction reaction (ORR). It is considered to be inherently sluggish and requires the application of significant overpotential, which translates directly to loss of power. The only effective way to overcome this barrier is electrocatlysis. The best and most common catalysts for this reaction today are based on Pt, which has intrinsic disadvantages such as low selectivity, high sensitivity for degradation at high operating potentials in addition to its scarcity and the high price derived from it. According to the US-DOE, 43% of the total cost of the cell is the price of the catalyst itself. Hence the motivation for the design and utilization of cheaper, precious group metal-free (PGM-free) catalysts for oxygen reduction reaction.
In this talk I will survey the progress made since the early days of PGM-free catalysts design in the mid 1960’s until today and beyond. I will focus on the five main groups of this class of catalysts studied today, their advantages and disadvantages will be explained and the frontiers for more durable and active PGM-free catalysts will be discussed. I will also go over the economy of these catalysts and their utilization in fuel cells today.