{"69321":{"#nid":"69321","#data":{"type":"news","title":"Improving Fuel Cell Durability Starts With Failures","body":[{"value":"\u003Cp\u003EFuel cells can be expensive and they typically don\u0027t last as long as their internal combustion counterparts.\n\u003C\/p\u003E\n\u003Cp\u003EResearchers in the Georgia Tech Research Institute\u0027s (GTRI) Center for Innovative Fuel Cell and Battery Technologies believe that understanding how and why fuel cells fail is the key to both reducing cost and improving durability.\n\u003C\/p\u003E\n\u003Cp\u003ECenter director Tom Fuller has been trying to solve what he deems the top three durability problems since he joined GTRI from United Technologies three years ago. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022My philosophy is if we can really understand the fundamentals of these failure mechanisms, then we can use that information to guide the development of new materials or we can develop system approaches to mitigate these failures,\u0022 said Fuller, who is also a professor in Georgia Tech\u0027s School of Chemical and Biomolecular Engineering (ChBE).\n\u003C\/p\u003E\n\u003Cp\u003EThe problems Fuller is addressing include chemical attack of the membrane, carbon corrosion and platinum instability. Fuller described progress toward solving these problems last month at the 212th Electrochemical Society Meeting.\n\u003C\/p\u003E\n\u003Cp\u003EIn a typical fuel cell, hydrogen is delivered to the anode side of the cell that contains a catalyst, such as platinum. The platinum splits the hydrogen molecules (H2) into hydrogen ions and electrons. On the cathode side of the fuel cell, an oxidant such as a stream of oxygen or air is delivered. \n\u003C\/p\u003E\n\u003Cp\u003EWith a proton exchange membrane in the middle, only hydrogen ions can travel through the membrane to the cathode. Electrons travel on a different path through the electrical circuit to the cathode, creating an electrical current. At the cathode, the hydrogen ions combine with oxygen and the electrons that took the longer path to form water, which flows out of the cell.\n\u003C\/p\u003E\n\u003Cp\u003EFuller\u0027s research shows that the membrane, commonly made of a synthetic polymer, is prone to attack by free radicals that create holes in the barrier. The free radicals are formed by the decomposition of hydrogen peroxide (H2O2), a strong oxidizing chemical that can form near the membrane.\n\u003C\/p\u003E\n\u003Cp\u003ESince a typical membrane is approximately 25-50 micrometers thick, or about the thickness of a human hair, it\u0027s impossible to see the degradation peroxide causes with the naked eye. \n\u003C\/p\u003E\n\u003Cp\u003EIn a paper published in March in the \u003Cem\u003EJournal of Power Sources\u003C\/em\u003E, Fuller and professor Dennis Hess, research scientist Galit Levitin and graduate student Cheng Chen, all from ChBE, used X-ray photoelectron spectroscopy (XPS) to study the membrane degradation. This work was funded by GTRI, ChBE and the Lawrence Berkeley National Laboratory. \n\u003C\/p\u003E\n\u003Cp\u003EThe researchers chose XPS because it is a quantitative technique that uses X-rays to measure the presence and quantity of chemical elements and the formation and breakage of chemical bonds within a material.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We were able to see chemical differences in the membrane with XPS when it went through the degradation process,\u0022 explained Fuller. \u0022Now we\u0027re trying to figure out what really limits or controls the rate of degradation.\u0022\u003C\/p\u003E\n\u003Cp\u003EThe solution will be difficult because the formation of hydrogen peroxide requires only hydrogen and oxygen to be present. Since these chemicals are readily available in fuel cells, hydrogen peroxide can be produced many ways. The problem is further complicated because free radicals are short lived and difficult to detect.\n\u003C\/p\u003E\n\u003Cp\u003EFuller will leave the actual engineering of new non-degrading membranes to the materials scientists, but what he has learned can guide what properties new membranes should have and how they can be tested for degradation.\n\u003C\/p\u003E\n\u003Cp\u003EAnother challenge with low temperature fuel cells is that a blockage can occur on the anode side of the fuel cell, possibly from a water drop formed in the fuel channel. The blockage causes carbon (used to support the platinum) to corrode, turn into carbon dioxide and leave the fuel cell as a gas. Frequently starting and stopping the fuel cell also causes this mode of failure.\n\u003C\/p\u003E\n\u003Cp\u003EThis can be catastrophic for the fuel cell because without carbon, the platinum catalyst layer collapses and disappears.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022If this happens, the fuel cell can be destroyed in days rather than years,\u0022 noted Fuller.\n\u003C\/p\u003E\n\u003Cp\u003EThis problem is more common in non-stationary fuel cell applications, such as cars that require the fuel cell to start and stop when the vehicle is turned on and off. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022Researchers know this problem exists, but we\u0027re trying to build physics-based detailed models to evaluate different fuel cell designs that will reduce the susceptibility to this type of corrosion,\u0022 said Fuller, who\u0027s working on this project with Norimitsu Takeuchi from Toyota\u0027s material research department and students Kevin Gallagher and David Wong with funding from Toyota. \n\u003C\/p\u003E\n\u003Cp\u003EThe models can also be used to determine options for controlling and mitigating this problem to find a more effective alternative material that is more resistant to corrosion.\u003C\/p\u003E\n\u003Cp\u003EAnother problem with fuel cells cycling on and off is that platinum has a small but finite solubility in the acidic membrane given the high electrical potential and oxidizing environment at the cathode.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Platinum is one of the most expensive parts of the fuel cells, so researchers study how to decrease the amount necessary to run a fuel cell,\u0022 explained Fuller. \u0022But if there is less platinum in the fuel cell to begin with, you can\u0027t afford to lose any by it dissolving.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EWhen the platinum layer dissolves, a band of platinum typically forms inside the membrane. Fuller, GTRI senior research engineer Gary Gray and graduate student Wu Bi, developed a model to predict where the platinum band would form to help to understand why it was happening. This work was published in March in \u003Cem\u003EElectrochemical and Solid-State Letters\u003C\/em\u003E.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We found that the platinum can also be deposited throughout the membrane and it can move around to different places, but whenever it leaves where it\u0027s supposed to be, it\u0027s no longer effective,\u0022 said Fuller.\n\u003C\/p\u003E\n\u003Cp\u003EFuller aims to understand these very small platinum particles by modeling the transport and thermodynamics of the particles in fuel cell systems. This work was funded by Hyundai Motors Corporation.\n\u003C\/p\u003E\n\u003Cp\u003EA recent gift of $200,000 from the Hartley Foundation will allow Fuller to purchase new research equipment and continue studying the degradation of fuel cells and how to improve\/extend the life cycle and technology of these energy devices.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Fuel cell failure can occur through many different mechanisms,\u0022 added Fuller. \u0022Results from these three projects show that new materials, new manufacturing processes and new designs are required to improve the durability of fuel cells and in turn lower costs.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe Lawrence Berkeley National Laboratory funding came from the Assistant Secretary for Energy Efficiency and Renewable Energy in the Office of Hydrogen, Fuel Cell and Infrastructure Technologies of the U.S. Department of Energy under contract number DE-AC02-05CH11231 through subcontract 6804755.\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 100\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\n\u003C\/strong\u003E\u003C\/p\u003E\n\u003Cp\u003EMedia Relations Contacts: Abby Vogel (404-385-3364); E-mail: (\u003Ca href=\u0022mailto:avogel@gatech.edu\u0022\u003Eavogel@gatech.edu\u003C\/a\u003E) or John Toon (404-894-6986); E-mail: (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Kirk Englehardt (404-407-7280); E-mail: (\u003Ca href=\u0022mailto:kirk.englehardt@gtri.gatech.edu\u0022\u003Ekirk.englehardt@gtri.gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ETechnical Contact:\u003C\/strong\u003E Tom Fuller (404-407-6075 or 404-894-2898); E-mail: (\u003Ca href=\u0022mailto:tom.fuller@gtri.gatech.edu\u0022\u003Etom.fuller@gtri.gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter:\u003C\/strong\u003E Abby Vogel\n\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Research will lead to better fuel cell materials and designs"}],"field_summary":[{"value":"Understanding how and why fuel cells fail is the key to both reducing cost and improving durability, according to researchers in the Georgia Tech Research Institute\u0027s (GTRI) Center for Innovative Fuel Cell and Battery Technologies.","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers improve fuel cells by studying failures"}],"uid":"27206","created_gmt":"2007-11-22 01:00:00","changed_gmt":"2016-10-08 03:03:24","author":"Abby Vogel Robinson","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2007-11-28T00:00:00-05:00","iso_date":"2007-11-28T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"69322":{"id":"69322","type":"image","title":"Tom Fuller","body":null,"created":"1449177252","gmt_created":"2015-12-03 21:14:12","changed":"1475894606","gmt_changed":"2016-10-08 02:43:26"},"69323":{"id":"69323","type":"image","title":"Tom Fuller fuel cell membrane","body":null,"created":"1449177252","gmt_created":"2015-12-03 21:14:12","changed":"1475894606","gmt_changed":"2016-10-08 02:43:26"},"69324":{"id":"69324","type":"image","title":"Tom Fuller fuel cell","body":null,"created":"1449177252","gmt_created":"2015-12-03 21:14:12","changed":"1475894606","gmt_changed":"2016-10-08 02:43:26"}},"media_ids":["69322","69323","69324"],"related_links":[{"url":"http:\/\/dx.doi.org\/10.1149\/1.2712796","title":"Electrochemical and Solid-State Letters Article"},{"url":"http:\/\/dx.doi.org\/10.1016\/j.jpowsour.2007.03.037","title":"Journal of Power Sources Article"},{"url":"http:\/\/www.chbe.gatech.edu\/","title":"School of Chemical \u0026 Biomolecular Engineering"},{"url":"http:\/\/www.fcbt.gatech.edu\/","title":"Center for Innovative Fuel Cell and Battery Technologies"},{"url":"http:\/\/www.chbe.gatech.edu\/fac_staff\/faculty\/fuller.php","title":"Tom Fuller"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"141","name":"Chemistry and Chemical Engineering"},{"id":"145","name":"Engineering"},{"id":"135","name":"Research"}],"keywords":[{"id":"610","name":"carbon"},{"id":"7530","name":"durability"},{"id":"7245","name":"failure"},{"id":"2044","name":"Fuel Cell"},{"id":"7440","name":"membrane"},{"id":"7531","name":"platinum"},{"id":"3517","name":"power"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cstrong\u003EAbby Robinson\u003C\/strong\u003E\u003Cbr \/\u003EResearch News and Publications\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=avogel6\u0022\u003EContact Abby Robinson\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-385-3364\u003C\/strong\u003E","format":"limited_html"}],"email":["abby@innovate.gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}