Toward a Sustainable Energy Future

About 25 years ago, and morethan 100 years after JulesVerne wrote The Mysterious

Island, scientists and engineers at LosAlamos began an R&D program intofuel cells, a program that today leadsour nation and the world toward amodern version of Jules Verne’sprophetic vision. In the “hydrogeneconomy,” hydrogen provides themeans to carry the energy trapped incoal, uranium, or wind, to our homes,cars, or offices. Fuel cells provide aclean, efficient energy-conversiontechnology. Together, hydrogen andfuel cells offer the promise of a sus-tainable energy future.

Hydrogen was first isolated as aseparate element by English chemistHenry Cavendish in 1766. Called

“inflammable air” upon discovery, thecolorless, odorless gas was laternamed for its propensity to formwater on combustion in air(hydro·gen). Sixty-five years later, in1839, Sir William Grove, a Britishjurist and amateur physicist, inventedthe hydrogen-oxygen fuel cell,although Christian FriedrichSchonbein (who discovered ozone andinvented guncotton) had demonstratedthe basic electrochemistry a year ear-lier. The overall reaction combineshydrogen gas (H2) with oxygen gas(O2) to form water and generate heat:

2H2 + O2 → 2H2O + heat . (1)

The reaction proceeds through twosteps, or half reactions, each con-

strained to take place on a differentside of a reaction cell (the anode sideand the cathode side). The two sidesof the reaction cell are separated byan all-important electrolyte “barrier.”Hydrogen gas is fed to the anode,where a metal catalyst—typically,platinum—facilitates the breakdownof the hydrogen gas into hydrogenions and electrons. The positivelycharged ions move through the elec-trolyte to the cathode, but the nega-tively charged electrons must take anexternal conducting path. Once at thecathode, the electrons combine withthe ions and the oxygen gas—againwith the help of a catalyst—to pro-duce water (see Figure 1).

The flow of electrons through theexternal conduction path constitutes

240 Los Alamos Science Number 28 2003

Toward a Sustainable Energy FutureFuel cell research at Los Alamos

Kenneth R. Stroh

“But in the end, my dear Cyrus, all this industrial and commercial development which you predict will continually grow, is it not indanger of coming to a halt sooner or later?… you can’t deny that one day all the coal will be used up…And what will they burn inthe place of coal?”“Water,” replied Cyrus Smith.“Water!” exclaimed Pencroft. “Water to heat steamships and locomotives, water to heat water?”“Yes, but water decomposed into its basic elements…Yes, my friends, I believe that water will one day serve as our fuel, that thehydrogen and oxygen which compose it, used alone or together, will supply an inexhaustible source of heat and light…”

—Jules Verne, The Mysterious Island (1874)

an electric current that can do work.Thus, the fuel cell is a source of elec-tric power that, like a battery, convertsthe chemical energy in the hydrogenfuel directly to electricity. Unlike abattery, the fuel cell has the reactantsexternally fed and will continue toprovide full output as long as hydro-gen and oxygen are supplied.

While the electrochemistry of thefuel cell was well understood yearsago, enthusiasts discovered that engi-neering a practical device was diffi-cult. The platinum catalyst is veryexpensive, and there are significantissues regarding the accessibility ofgases to the electrodes, the purity ofthe gases, the electrolyte composition,the removal of water, and so on, all ofwhich affect fuel-cell performance.Fuel-cell technology languished untilWorld War II, when Francis TomBacon, an engineer at CambridgeUniversity, refined the electrochemicalcell and built a complete power sys-tem. Decades later, when the NationalAeronautics and Space Administration(NASA) sought a compact, light-weight, reliable, and efficient powersystem for manned space flight, thetechnology really “took off.” Whatemerged from approximately 200fuel-cell R&D contracts let by NASAduring the Apollo program was theGeneral Electric (GE) solid polymerelectrolyte (SPE™) fuel cell, whichwas used in the Gemini space cap-sules. GE’s technology subsequentlybecame known as the polymer elec-trolyte membrane (PEM) fuel cell,and it has been the main focus of fuel-cell work at Los Alamos NationalLaboratory since 1977.

The PEM Fuel Cell. The center-piece of the PEM fuel cell is the solid,ion-conducting polymer membrane,which replaces the liquid electrolyte.Looking much like a thick sheet ofplastic food wrap, the membrane istypically made from a tough, Teflon-like material called NafionTM. This

material is unusual in that, when satu-rated with water (hydrated), it con-ducts positive ions but not electrons—exactly the characteristics needed foran electrolyte barrier.

The membrane is sandwichedbetween the anode and cathode elec-trode structures—porous conductingfilms, about 50 micrometers thick,consisting of carbon particles thathave nanometer-size platinum parti-cles bonded to them. Because the plat-inum particles have such a high sur-face area, the total catalytic activity ofan electrode can be enormous. Theelectrodes are porous so that gaseshave ready access to the full surfacearea (see Figure 2).

In addition to having catalytic andelectric conducting properties, theelectrodes—and the backing materialthat supports them—are crucial to thewater management of the cell.

Ironically, even though water is aproduct of the fuel-cell reaction, boththe hydrogen and oxygen gas streamsmust be humidified to keep the poly-mer membrane hydrated. If there istoo little water, the membrane beginsto lose the ability to conduct ions.However, if there is too much water, itfloods the porous electrodes and pre-vents the gases from diffusing to thecatalytically active sites. Thus, waterproduced at the cathode must continu-ally be removed. Water managementand the control of gas flows in and outof the cell are the keys to efficient celloperation.

Each PEM fuel cell develops apotential of about 0.4 to 0.8 voltsbetween the anode and cathode,depending on temperature, gas pres-sure, flow, and other operating condi-tions. Higher voltage is obtained whena number of cells are placed in series

Number 28 2003 Los Alamos Science 241

Toward a Sustainable Energy Future

O2H2

H+

Vent

Anode side

Reductionhalf reaction

2H2 → 4H+ + 4e–

Oxidationhalf reaction

4H+ + 4e– + O2 → 2H2O

Cathode side

Vent

Platinumelectrode

Electrolytesolution/barrier

Figure 1. Fuel Cell BasicsA fuel cell takes hydrogen gas and combines it with oxygen gas to produce electricity.The only “waste” products are water and heat. As shown in this conceptual liquid-elec-trolyte cell, hydrogen gas is fed to the anode side of the cell, and oxygen gas is fed tothe cathode side. The two electrodes are identical, each consisting of an electrical conductor studded with platinum. At the anode, the platinum catalyzes the breakdownof hydrogen gas into hydrogen ions and electrons (reduction half reaction). The ionsare conducted to the cathode by the electrolyte solution, but the electrons, which donot move through the electrolyte, flow to the cathode along the connecting wire. Theplatinum catalyzes the water-forming reaction involving ions, electrons, and oxygen(oxidation half reaction). Because of the separation of charge, a voltage potential ofabout half a volt is established between the anode and cathode.

to create a “fuel-cell stack.” Becausethe electrochemically active cross-sec-tional area of each cell has a charac-teristic current density (typically sev-eral hundred to more than a thousandmilliamperes per square centimeter,depending on operating conditions),the desired electrical current for a spe-cific application can be achieved bychanging the cross-sectional area ofthe stack. Through proper design andselection of operating conditions,stacks producing as much as 100 kilo-watts have been achieved.

The PEM cells operate at relativelylow temperatures (about 80º Celsius),a feature that makes them attractivefor applications requiring multiplestart-stop cycles, such as passengervehicles. Because a fuel-cell-basedelectric propulsion system offers twoto three times the energy efficiency ofan internal combustion engine andassociated drive train, the transporta-tion sector is a driving force accelerat-

ing fuel-cell R&D. Besides energyefficiency, fuel cells offer low emis-sions (approaching zero if the hydro-gen is made cleanly), and they helpwith energy and economic securitybecause hydrogen can be made from adiverse array of domestic energyresources.

In the near term, hydrogen can beproduced from natural gas, fossilfuels, biomass, or through electrolysisof water (separating H2O into hydro-gen and oxygen in a process akin torunning a fuel cell in reverse). Theelectricity needed to run theseprocesses would come from fossil-fuel and nuclear power plants, or fromrenewable resources such as the sunand the wind. In the longer term,hydrogen can be produced by use ofheat from nuclear reactors and a ther-mochemical process to do the waterelectrolysis. In another concept, zero-emission coal systems could sequestercarbon in the process of separating

hydrogen. Hydrogen, therefore, pro-vides a means to carry the energy con-tained in coal or nuclear fuels to anend user. It is also possible to producethe hydrogen entirely from renewableresources and thus enable a truly sus-tainable energy future.

Los Alamos R&D

Work at Los Alamos in the last25 years has been enabling for theemerging fuel-cell industry, and theLaboratory holds several seminalpatents required by would-be productdevelopers. Arguably, the break-through that brought the PEM fuel cellout of the space program and madepossible its consideration as a ubiqui-tous power-conversion technology wasour development in the late 1980s andearly 1990s of the low-platinum PEMelectrodes described earlier.

Before these developments, state-



Figure 2. The PEM Fuel Cell(a) The side chains of the NafionTM polymer making up the mem-brane contain a sulfonic acid ion cluster, SO3

–H+.The negativeSO3

– ions are permanently attached to the side chain, but whenthe membrane becomes hydrated, the H+ ions can attach towater molecules and form H3O+ ions.These ions are free tomigrate from SO3

– site to SO3– site, making the hydrated mem-

brane an effective conductor of H+ ions. (b) The electrodes oneach side of the membrane consist of sootlike carbon particleswith nanometer-size platinum particles bonded to them. Runningbetween the carbon particles are NafionTM polymers to aid in ion

conductivity.The porous electrodes are pressed against the PEM.(c) The membrane and electrode assembly is sandwichedbetween backing layers and end plates.The porous, electricallyconducting backing layers provide a way for incoming gases todiffuse uniformly to the electrodes and help in water manage-ment.The conducting end plates channel electrons to externalcircuits. Channels cut into the plates create a circuitous flow fieldfor the gases and provide a way to remove water on the cathodeside (see the opening graphic).This cell can be linked in serieswith other cells to make a higher-voltage fuel cell stack.

Polymerelectrolytemembrane

Electronsconducted

throughelectrodeby carbon

particles

H+ ions conductedthrough

membrane

Carbonparticle

Platinumbonded

to carbon

Anode Cathode

Air (O2) in

H2 out

Water andair out

Anode backing

Membrane/electrode assembly

Cathodebacking

Cathodecurrentcollector

Anodecurrentcollector

CF

O

CF2CF2

CF3

CF2

CF

O

CF2

CF2

SO3– H+

(a) (b) (c)

Reduction

Oxidation

of-the-art PEM “electrodes” had rela-tively large platinum particles embed-ded (basically, rammed) directly intothe membrane. To maintain electronconductivity, those electrodes requiredvery large amounts of platinum. Thecost of platinum was not an issue forNASA, but it stifled any commercialapplications.

Low-platinum porous electrodeshad already been developed for liquidelectrolyte systems, but their initialapplication to the dry PEM cell wasunsuccessful. The sootlike carbon par-ticles did not conduct ions very well,and in the absence of a liquid elec-trolyte, most ions had no conductingpath to the membrane.

The Los Alamos breakthroughcame when Ian Raistrick applied asolution that contained dissolvedNafionTM material to the surface ofthe porous electrode. Once the solu-tion dried and the electrodes werepressed to the membrane, theNafionTM material provided an ion-conducting path from the PEM to theplatinum particles. Mahlon S. Wilsonlater invented methods for fabricatingrepeatable thin-film electrodes bondedto the PEM membrane—the so-calledmembrane electrode assembly (MEA).In combination, these techniques havedramatically lowered the required pre-cious-metal catalyst loadings by a fac-tor of more than 20 while simultane-ously improving performance. Theyare now used by fuel-cell manufactur-ers and researchers worldwide.

Another Los Alamos innovationdramatically improves cell toleranceto hydrogen impurities and perform-ance in the presence of impurities,enabling low-temperature PEM fuelcells to operate not only with purehydrogen, but also with hydrogen-richgas streams derived from hydrocarbonfuels (such as gasoline, methanol,propane, or natural gas). Such gasstreams invariably contain traceamounts of carbon monoxide (CO), aspecies that poisons the catalyst by

getting adsorbed and lowering theactive surface area. The Los Alamostechnique, invented by ShimshonGottesfeld, injects small amounts ofoxygen-containing air into the fuelstream before it enters the fuel cell.Even at PEM operating temperatures,the oxygen can oxidatively removethe CO from the catalyst surface, thusmaintaining electrode surface area forthe hydrogen oxidation reaction.

Other significant Los Alamos tech-nology advances include developmentof processes to generate hydrogen-rich gas streams on demand fromgaseous and liquid hydrocarbon fuels,significant improvement of directmethanol fuel cells (cells that run onmethanol instead of hydrogen), devel-opment of fuel-cell test proceduresand performance characterizationmethodologies, and fundamental data-supported modeling of fuel cell per-formance. Technology transfer has

been facilitated by publishing, licens-ing, student programs, direct trainingof industrial personnel, cooperativeR&D agreements, and migration ofour technical staff and students toindustry.

The Electrochemical Engine

Our researchers have worked close-ly with industry from the beginning ofthe Los Alamos fuel-cell program.One key example was the establish-ment of the Los Alamos–GeneralMotors (GM) Joint DevelopmentCenter (JDC) at the Laboratory in1991, funded by GM and theDepartment of Energy (DOE). TheJDC effort was focused on develop-ment of the electrochemical engine, acomplete PEM fuel-cell power systemfueled by methanol (shown inFigure 3), which was converted ondemand to a hydrogen-rich gas by asteam-reformation process. At thattime, liquid fuel was considered cru-cial to the acceptance offuel-cell-powered vehicles becauseusing liquid fuel would allowexploitation of the transportation sec-tor’s mature fuel-distribution infra-structure.

In the steam-reforming process,methanol (CH3OH) reacts with watervapor in a series of controlled catalyt-ic reactors to form a mixture ofhydrogen and carbon dioxide. Thecarbon dioxide flows through thePEM cell with little effect, and thehydrogen is consumed in the fuel-cellreaction. The JDC team worked on allaspects of the power system: fromoptimizing the membrane electrodeassembly to providing system integra-tion, modeling, and testing. At thesame time, a DOE-funded coreresearch activity, in what is now theElectronic and ElectrochemicalMaterials and Devices Group, wasmaking enabling breakthroughs thatwere soon incorporated into the elec-



Figure 3. Equipment and TestingBrent Faulkner is pictured (photo takenaround 1994) with the 10-kW electro-chemical engine, a complete PEM fuel-cell power system, developed through ajoint collaboration between theLaboratory and GM. The insulated com-ponents to the right are part of themethanol steam reformer that produced,on demand, hydrogen-rich gas from aliquid fuel. The two 5-kW PEM fuel cellstacks (made by Ballard) have blue end-plates and can be seen at left. Additionalequipment required to complete thepower system is out of the photo frame.

trochemical engine. Phase I of theproject developed and demonstratedthe complete 10-kilowatt (gross elec-tric) electrochemical engine shown inFigure 3. Phase II extended this workto a stand-alone, 30-kilowatt (net elec-tric) engine.

As Phase II neared its end, GMtook the knowledge and expertisegained at the JDC and established acorporate fuel-cell R&D center inupstate New York. In a recent letter tothe Laboratory director, the GM direc-tor of fuel-cell activities noted,“General Motors and Los Alamoshave a long and successful historyworking together to research anddevelop fuel cells for automobiles.This collaboration, supported by theDepartment of Energy, serves as thetechnical foundation for the intensivedevelopment effort in fuel cells atGeneral Motors today.”

After the electrochemical engineproject, the engineering researcheffort shifted away from methanol andtoward making “stack-quality gas”from gasoline. This work was done inan effort to further reduce the fuelinfrastructure barrier to commercial-ization of fuel-cell-powered vehicles.The fundamental fuel-cell researchand development also put an increasedemphasis on optimizing fuel-cell per-formance and on achieving durabilityin “gasoline reformate,” the product ofgasoline processing typically consist-ing of 40 percent hydrogen, 18 per-cent carbon dioxide, 30 percent nitro-gen, 12 percent water, less than 10parts per million carbon monoxide,and unspecified “other impurities.”Gasoline reforming is typicallyaccomplished by partial oxidation ofgasoline to provide the endothermicheat of reaction required for subse-quent process steps, including steamreforming of the remaining hydrocar-bons and conversion of the residualcarbon monoxide to carbon dioxideand hydrogen by reaction with water(the “water-gas shift”).

In 1997, a team from theEngineering Sciences andApplications’ Energy and ProcessEngineering Group sent 2200 poundsof equipment to Cambridge,Massachusetts, by air freight to inte-grate a Los Alamos fuel-productcleanup system with a gasolinereformer developed by Arthur D. Littleand a PEM fuel-cell stack developedby Plug Power. (Los Alamos also tooka precommercial Ballard stack fortesting.) To great acclaim, the “inte-grated” system generated the world’sfirst electrical power from a low-tem-perature fuel cell operating on gaso-line reformate. The Laboratory-indus-try team received the Partnership for aNew Generation of Vehicles Medal ina 1998 ceremony at the White House.

Although technology developmentover the last two decades has beendramatic, PEM fuel cells are still tooexpensive and do not have the powerdensity, durability, or reliability to beeconomically and functionally com-petitive with conventional power-con-version devices. Today’s developmentprogram is oriented toward reducing

costs through materials substitutions,performance improvement, and sys-tem simplification and increasingdurability through understanding per-formance degradation and life-limit-ing effects.

In 2003, the program directionshifted. There is now a significantfocus on PEM fuel cells running onpure hydrogen stored onboard thevehicle. This change in emphasis,embodied in the president’s FreedomCooperative Automotive Researchand Fuel initiatives, resulted from thedesire to reduce system complexity,thereby reducing cost and improvingreliability, and the desire to minimizethe country’s dependence on import-ed oil while maximizing environmen-tal benefits. However, storing enoughhydrogen onboard to enable a 350-mile driving range is challenging andis still the subject of research.Because of this change in direction,our fuel-processing effort is shiftingto offboard stationary processors thatwould reform natural gas, propane, orliquid hydrocarbon fuels to gaseoushydrogen. There is also a growingemphasis on reforming “difficult”fuels such as diesel and Jet A (a com-mon aviation fuel) for use in auxil-iary power units for both civilian andmilitary applications.

The Future

Although the bulk of our fundinghas come from transportation pro-grams, fuel cells are inherently scala-ble, and one of the earliest marketintroductions is likely to occur in dis-tributed power systems. A fuel cell sit-ting beside a home, using reformednatural gas or propane, would providenot only electricity but also “waste”heat that could be captured andexploited for space heating and hot-water production. Such heat andpower systems could convert fuelchemical energy into useful products



Figure 4. The Consumer MarketPresident George W. Bush tries out acellular telephone powered by a DMFC,while Bill Acker of MTI MicroFuel Cellslooks on. The fuel cell is in thePresident’s hand and is connected tothe phone by wire. The methanol fuel isstored in a small plastic capsule that isinserted into the cell. MTI MicroFuelCells is commercializing Los Alamostechnology under license. (White Housephoto by Paul Morse.)

with close to 75 percent efficiency, farexceeding what a utility power plantcan achieve. Furthermore, by placingthe generating asset near the end use,we would avoid electrical transmis-sion losses. The resulting distributedpower system would be much morerobust.

Still, the first large-scale commer-cialization of fuel cells is likely tooccur in the portable electronics mar-ket, because fuel-cell power systemsoffer greater energy densities than bat-teries. The miniature fuel cells devel-oped for this application rely on a LosAlamos development that adapted andoptimized the basic PEM technologyto use dilute methanol as the fuel. Themethanol molecule (CH3OH) can beconsidered a high-energy-densityhydrogen carrier. The methanol isdirectly oxidized at the anode in amultistep process, and protons aretransported across the polymer elec-trolyte membrane just as they are in ahydrogen fuel cell. Although directmethanol fuel cells (DMFCs) are lessefficient than hydrogen fuel cells andrequire more expensive catalysts, theyseem a good match for hand-heldelectronics and small portable applica-tions, in which a 1-watt, state-of-the-art battery can cost $100 (or $100,000per kilowatt)—refer to Figure 4.

The Laboratory has also assembledan impressive intellectual-propertyportfolio in DMFC technology.Licensing and royalty revenues fromhydrogen fuel-cell and DMFC portfo-lios generate about one quarter of theannual intellectual-property revenuefor the Laboratory.

Citizen awareness of the conceptsof energy security, economic security,and sustainability are growing.Because of increasing bipartisan polit-ical support and the continuing inno-vation and commitment of our world-class research scientists, engineers,and technicians, we expect that theLaboratory’s contributions to solvingthese complex national and global

problems will only increase in thefuture. President Bush’s budgetrequest for fiscal year 2003 containedlanguage to establish a fuel-cellNational Resource Center at LosAlamos to address “. . . technical bar-riers to polymer electrolyte membranefuel-cell commercialization.”

While the designation of thisNational Resource Center and detailsof the center’s work scope, operations,and funding requirements are subjectto further discussion, we believe thecenter, if established, will focus onclose collaboration with industry, uni-versities, and other national laborato-ries, and will perform fundamentalresearch to enable development of thenext generation of fuel cells and relat-ed technologies, which will featurereduced cost, higher performance, andincreased durability. The center willalso provide resources in the form ofaccess to the existing knowledge base,experts in the field, and state-of-the-art experimental and analytical capa-bilities and could provide a magnetfor regional economic development. �

Acknowledgments

Many people have contributed tothe success of this program over thelast 25 years. Current team membersinclude Peter Adcock, Guido Bender,Rod Borup, Eric Brosha, AmandaCasteel, Jerzy Chilistunoff, JohnDavey, Christian Eickes, RobertFields, Fernando Garzon, DennisGuidry, Mike Inbody, Karl Jonietz,David King, Dennis Lopez,Rangachary Mukundan, SusanPacheco, John Petrovic, Piotr Piela,Bryan Pivovar, Geri Purdy, JohnRamsey, Tommy Rockward, JohnRowley, Andrew Saab, TroySemelsberger, Wayne H. Smith, TomSpringer, Jose Tafoya, FranciscoUribe, Judith Valerio, Will Vigil,Mahlon S. Wilson, Jian Xie, PiotrZelenay, and Yimin Zhu. We also

want to acknowledge the support ofpeople in management, includingCharryl Berger, Paul Follansbee, RossLemons, Tom J. Meyer, RichardSilver, and Donna Smith.

Further Reading

Gottesfeld, S. May 1990.“Preventing COPoisoning in Fuel Cells,” U.S. Patent No.4,910,099.

Raistrick, I. October 1989. “ElectrodeAssembly for Use in a Solid PolymerElectrolyte Fuel Cell,” U.S. Patent No.4,876,115.

Wilson, M. S. May 1993 “Membrane CatalystLayer for Fuel Cells,” U.S. Patent No.5,211,984.

———, August 1993. “Membrane CatalystLayer for Fuel Cells,” U.S. Patent No.5,234,777.

For more information, including references, afuel-cell primer, and an animation showing howa PEM fuel cell works, visit our website athttp://www.lanl.gov/mst/fuelcells/.



Kenneth Stroh came to the Laboratory to per-form his dissertation research in 1976. Heearned his bachelor’s,master’s, and doctoraldegrees in mechanicalengineering fromColorado StateUniversity before join-ing the technical staff ofthe Safety CodeDevelopment Group inthe Laboratory’s EnergyDivision in 1978. Since then, he has workedcontinuously on energy-systems design, analy-sis, and testing, with an emphasis in the lastdecade on fuel-cell power systems. Ken is cur-rently the Laboratory’s program manager forhydrogen, fuel cells and transportation and isthe hydrogen economy portfolio champion.

Toward a Sustainable Energy Future

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