Carbon nanofibers in the hydrogen industry

With our car­bon nanofibers (CNFs) fab­ri­ca­tion tech­nol­o­gy, we devel­op mate­ri­als engi­neer­ing solu­tions for use in the clean­tech industry.

Cur­rent­ly, we focus on improv­ing mem­brane-elec­trode assem­bly (MEA)—a com­po­nent in high-effi­cien­cy water elec­trolyz­ers and fuel cells. The com­po­nent enables the con­ver­sion of elec­tric­i­ty into hydro­gen and vice ver­sa. Thus, it’s a key com­po­nent in stor­age and trans­mis­sion of renew­able ener­gy and decar­boniz­ing of indus­try, trans­porta­tion, and heating.

Schemat­ic of a mem­brane-elec­trode assem­bly (MEA).
An array of car­bon nanofibers (CNFs) pre­cise­ly placed in rows and columns.

With a clever use of car­bon nanofibers, we can reduce the use of rare and expen­sive noble met­als by 50–70 per­cent, while dou­bling or tripling the active sur­face area of the pro­ton-exchange mem­brane (PEM) or anion exchange mem­brane (AEM) used in MEA.

Is your com­pa­ny inter­est­ed in build­ing more effi­cient elec­trolyz­ers or fuel cells? We are your tech­ni­cal part­ner. Con­tact us and we’ll tell you more.

Hydro­gen has many applications.

What is cleantech?

Clean tech­nol­o­gy, or clean­tech for short, refers to tech­nol­o­gy that simul­ta­ne­ous­ly ful­fills two objec­tives: First of all, it sig­nif­i­cant­ly reduces (i) the use of non-renew­able mate­ri­als and ener­gy, (ii) waste and mis­man­age­ment, and (iii) emis­sions and pol­lu­tion. Sec­ond­ly, it is com­pet­i­tive with its con­ven­tion­al coun­ter­parts, if not supe­ri­or to.

The term green tech­nol­o­gy, or green­tech for short, is often used inter­change­ably with clean tech­nol­o­gy. One might argue that there are sub­tle dif­fer­ences between them. The prob­lem is that nobody seems to agree on what these dif­fer­ences are. In prac­tice, they refer to the same thing.

Clean­tech can be used for many good pur­pos­es. The most worth­while is per­haps the reduc­tion of green­house gas­es in gen­er­al and car­bon diox­ide (CO2) in particular.

Carbon neutrality

Human emis­sions of green­house gas­es have giv­en rise to glob­al warm­ing, lead­ing to dev­as­tat­ing cli­mate changes. To not ruin the world we have inher­it­ed and must pass on to future gen­er­a­tions, we must achieve car­bon neu­tral­i­ty—a state of net-zero green­house gas­es mea­sured in terms of car­bon diox­ide equivalence.

More than 130 countries—including the Unit­ed King­dom and the Euro­pean Union (except for Poland)—and many com­pa­nies, cities, and finan­cial institutions—have agreed to reduce emis­sions to net-zero by 2050.

Hydro­gen (H2) has an essen­tial role in achiev­ing this goal. Accord­ing to a report by the Hydro­gen Coun­cil in col­lab­o­ra­tion with McK­in­sey & Com­pa­ny, hydro­gen can con­tribute 20 per­cent of the total abate­ment need­ed in 2050. But then it has to be green hydro­gen or low-car­bon hydrogen.

Green hydrogen and low-carbon hydrogen

About 95 per­cent of com­mer­cial hydro­gen in the US is pro­duced by steam methane reform­ing (SMR) of nat­ur­al gas. The process results not only in hydro­gen but also in mas­sive emis­sions of car­bon dioxide.

The pro­duc­tion of one met­ric tonne of hydro­gen pro­duces up to 13 tonnes of car­bon diox­ide. SMR is as far from clean tech­nol­o­gy as it gets.

Anoth­er dirty method is the gasi­fi­ca­tion of car­bon-based raw mate­ri­als, such as oil, coal and bio­mass. By its very nature, this also gives rise to sig­nif­i­cant car­bon diox­ide emissions.

The only com­mer­cial­ly viable method of pro­duc­ing hydro­gen that does not give rise to car­bon emis­sions is the elec­trol­y­sis of water. Elec­trol­y­sis of water is the process of run­ning a cur­rent through water to split water mol­e­cules into their con­stituent parts: hydro­gen and oxygen.

Hydro­gen pro­duced by water elec­trol­y­sis is not enough to con­tribute to car­bon neu­tral­i­ty. The elec­tric pow­er used in the pro­duc­tion must also have been pro­duced with no green­house gas emis­sions or at least sub­stan­tial­ly low­er emis­sions than con­ven­tion­al fos­sil fuel pow­er gen­er­a­tion. Such hydro­gen is called low-car­bon hydro­gen. If the elec­tric­i­ty orig­i­nates from a renew­able source, it is called green hydro­gen.

The Euro­pean Union uses def­i­n­i­tions that can be expressed as follows:

Grey hydro­gen is pro­duced with a car­bon foot­print greater or equal to 36.4 gram car­bon diox­ide equiv­a­lent per mega­joule (regard­less of the ener­gy source).

Low-car­bon hydro­gen is pro­duced with a car­bon foot­print low­er than 36.4 gram car­bon diox­ide equiv­a­lent per megajoule.

Green hydro­gen is low-car­bon hydro­gen where the ener­gy source is renewable.

Green hydrogen to rescue

Green hydro­gen is crit­i­cal to enabling a car­bon-neu­tral ener­gy sys­tem. Elec­tric­i­ty can be con­vert­ed into ener­gy-rich hydro­gen, that can be stored for long peri­ods in large vol­umes, can be trans­port­ed long dis­tances, and can be tapped as fuel or con­vert­ed back into elec­tric­i­ty when need­ed. This has many pos­i­tive impli­ca­tions. Two examples:

Stor­ing ener­gy as hydro­gen when low-cost sur­plus ener­gy is avail­able and releas­ing it when need­ed enables con­tin­u­ous grid oper­a­tion with solar pan­els, wind tur­bines, wave pow­er plants, and oth­er renew­able ener­gy sources that are intermittent.

Trans­port­ing ener­gy as hydro­gen through pipelines or boats makes it pos­si­ble to extract high­ly com­pet­i­tive renew­able ener­gy in places that would oth­er­wise be out of the ques­tion due to their remoteness.

Stor­ing and trans­port­ing ener­gy is not the only way green hydro­gen (or at least low-car­bon hydro­gen) can low­er car­bon emissions.

Heavy industry becomes green industry

Green hydro­gen and low-car­bon hydro­gen are crit­i­cal for decar­boniz­ing industries.

First and fore­most, the car­bon emis­sions from indus­tries using grey hydro­gen would decrease sig­nif­i­cant­ly if they used green or low-car­bon hydro­gen instead. Take ammo­nia, for exam­ple. It is the sec­ond most com­mon­ly pro­duced chem­i­cal in the world. More than 80 per­cent is used as feed­stock for fer­til­iz­er. The rest are used in mak­ing paint, plas­tic, tex­tiles, explo­sives, and oth­er chem­i­cals. Ammo­nia pro­duc­tion in 2018 was 176 mil­lion met­ric tons and gen­er­at­ed around 500 mil­lion tons of car­bon diox­ide. A large part of these emis­sions comes from hydro­gen pro­duced by steam methane reform­ing. That method emits 13 tons of car­bon diox­ide per ton pro­duced hydrogen.

Sec­ond­ly, green hydro­gen or low-car­bon hydro­gen can be used as a new feed­stock to low­er car­bon emis­sions. A great exam­ple of this is the steel indus­try. Each ton of steel pro­duced in 2018 is esti­mat­ed to emit 2.2 tons of car­bon dioxide—equating to about 11 per­cent of glob­al car­bon diox­ide emis­sions. But it is pos­si­ble to make fos­sil-free steel by using green hydro­gen instead of car­bon or coke. Green hydro­gen makes it pos­si­ble to remove oxy­gen from the iron ore, which is a pre­req­ui­site for steel production.

Third­ly and last­ly, green or low-car­bon hydro­gen can be used for high-grade indus­tri­al heat­ing. An exam­ple is the cement indus­try, which accounts for 8 per­cent of glob­al car­bon diox­ide emis­sions. Emis­sions can be reduced by a third by using green hydro­gen to heat the cement kilns. (The remain­ing two-thirds come from the chem­i­cal reac­tion that pro­duces cement and must be cap­tured and stored or reduced by oth­er means.)

Decarbonizing of transportation

The indus­try is not the sole sig­nif­i­cant source of car­bon diox­ide emis­sions. Trans­port is an equal­ly big cul­prit, which needs to be decar­bonized. Again green or low-car­bon can be used.

Hydro­gen can be used as a fuel for heavy-duty trucks, coach­es, long-range pas­sen­ger vehi­cles, and trains. It can also be used as feed­stock for pro­duc­ing syn­thet­ic fuels for mar­itime ves­sels and aviation.

Rapid increase in demand for hydrogen

Accord­ing to the report, Hydro­gen for Net-Zero by Hydro­gen Coun­cil and McK­in­sey & Com­pa­ny, green and low-car­bon hydro­gen can be used to avoid 80 bil­lion tons (80 GT) of cumu­la­tive car­bon emis­sions from now through 2050. With an annu­al abate­ment poten­tial of sev­en bil­lion tons (7 GT) in 2050, hydro­gen can con­tribute 20 per­cent of the total abate­ment need­ed in 2050.

But then pro­duc­tion over the upcom­ing 30 years must increase more than sev­en times-from 90 to 660 mil­lion met­ric tons. And in just eight years (2030), pro­duc­tion will need to increase by more than 50 percent.

Glob­al hydro­gen demand by seg­ment until 2050. Source: Hydro­gen for Net-Zero by Hydro­gen Coun­cil and McK­in­sey & Company.

Rapid growth of production capacity

To meet the strong growth in demand for hydro­gen, pro­duc­tion capac­i­ty needs to be expand­ed rapid­ly. And indeed, we see a rapid growth in announced or start­ed projects to build hydro­gen pro­duc­tion facil­i­ties. In fact, the growth is so fast that the Hydro­gen Council’s growth fore­casts have had to be bumped up every year in recent years.

In the report, Hydro­gen for Net-Zero, Hydro­gen Coun­cil and McK­in­sey & Com­pa­ny writes that play­ers have announced more than 18 mil­lion tons of green and low-car­bon hydro­gen pro­duc­tion through 2030. (See fig­ure below.) Addi­tion­al announce­ments include near­ly 13 mil­lion tons of green and low-car­bon hydro­gen pro­duc­tion capac­i­ty with deploy­ment beyond 2030. The total green and low-car­bon hydro­gen pro­duc­tion vol­ume announced in 2021 exceeds 30 mil­lion tons—more than 30% of the cur­rent glob­al hydro­gen demand.

Announced green or low-car­bon hydro­gen pro­duc­tion vol­ume in a mil­lion tons. Source: Hydro­gen for Net-Zero by Hydro­gen Coun­cil and McK­in­sey & Company.

Skyrocketing demand of membrane-electrode assembly

Green hydro­gen and low-car­bon hydro­gen are pro­duced by elec­trol­y­sis. Put sim­ply, that is run­ning elec­tric­i­ty through water and gath­er­ing the released hydro­gen. The appa­ra­tus in which this is done is called an elec­trolyz­er.

Con­ven­tion­al tech­nol­o­gy—alka­line elec­trol­y­sis—is quite inef­fi­cient. The hydro­gen pro­duced con­tains only 45–65 % of the ener­gy input. Much bet­ter effi­cien­cy is pro­vid­ed by PEM elec­trol­y­sis. Up to 84 % of the ener­gy can be recov­ered, and the fig­ure is expect­ed to reach 86 % by 2030. Thus, the new elec­trolyz­ers being built will main­ly use PEM electrolysis.

The crit­i­cal com­po­nent of a PEM elec­trolyz­er is the mem­brane-elec­trode assem­bly (MEA). It is the unit where the elec­tric­i­ty in con­tact with water becomes hydro­gen and oxy­gen. Each pro­duc­tion plant has vast num­bers of these. Thus, the rapid growth of pro­duc­tion capac­i­ty implies that the demand for MEA will skyrocket.

Operation of membrane-electrode assembly

The mem­brane-elec­trode assem­bly (MEA) has at its heart a pro­ton-exchange mem­brane with cat­alyt­ic met­al par­ti­cles on its sur­faces, fol­lowed by porous mate­r­i­al to dif­fuse the released gas­es and out­er­most flat plate electrodes.

The con­ver­sion from elec­tric­i­ty to hydro­gen occurs at the con­tact sur­faces between the cat­alyt­ic par­ti­cles and the mem­brane. The more con­tact sur­faces there are, the more hydro­gen can be pro­duced. The dif­fi­cul­ty lies in get­ting the nanopar­ti­cles in the right place.

Why membrane-electrode assembly is expensive

Cur­rent­ly, one method used is to mix the cat­alyt­ic par­ti­cles into ink that is applied between the mem­brane and the porous mate­r­i­al. The prob­lem is that only a few of the cat­alyt­ic par­ti­cles end up right on the mem­brane. A vast major­i­ty is inside the ink and does not come into con­tact with the mem­brane. They are entire­ly wasted.

It wouldn’t be a big prob­lem if it weren’t for the cat­alyt­ic par­ti­cles, being rare and expen­sive noble met­als. On one side of the mem­brane, plat­inum is used, which on Jan­u­ary 10, 2022, costs 853 USD per troy ounce—that’s about 25.000 EUR/​kg. On the oth­er side, it’s even worse. It uses irid­i­um, which is very rare. Less than eight met­ric tons are mined year­ly. And the price on Jan­u­ary 10, 2022, is 6,100 USD per troy ounce—that’s about 175.000 EUR/​kg.

How Smoltek reduce the price

The solu­tion from Smoltek fix­ates nanopar­ti­cles of the cat­a­lyst met­als on car­bon nanofibers embed­ded into the mem­brane. This dra­mat­i­cal­ly reduces the amount of noble met­al need­ed while prac­ti­cal­ly every piece of them is put to use.

This is how we can reduce the use of rare and expen­sive noble met­als by 50–70 per­cent while dou­bling or tripling the active sur­face area of the pro­ton-exchange mem­brane (PEM) or an ion exchange mem­brane (AEM) used in MEA.

Achievements so far

This requires the abil­i­ty to fab­ri­cate, on the sur­face of the porous mate­r­i­al, near­est the mem­brane, a for­est of erect car­bon nanofi­bres in rows and columns. The nanofi­bres must be uni­form­ly dis­trib­uted at a dis­tance opti­mized to facil­i­tate the trans­port of reac­tants to the nanopar­ti­cles and gas away from them.

Of course, it also requires that par­ti­cles of plat­inum and irid­i­um, mea­sured in nanome­ters, can be cre­at­ed and attached to the sur­face and tip of the car­bon nanofibre.

Fur­ther­more, the car­bon nanofi­bres must have low elec­tri­cal resis­tance to allow cur­rent to flow between the elec­trode and the cat­a­lyst nanoparticles.

On top of all that, the car­bon nanofibers must be cor­ro­sion resis­tant because of the mem­branes which cre­ate an acidic elec­trolyte in con­tact with water.

Smoltek has devel­oped and patent­ed the tech­nol­o­gy to do all this.

Are you interested in partnering with us?

Our next step is to indus­tri­al­ize our solu­tion for car­bon nanofiber enhanced mem­brane-elec­trode assem­bly (CNF-MEA for short). We are there­fore look­ing for indus­tri­al partner(s) that, in close col­lab­o­ra­tion with us,

  • builds and test pro­to­types with dif­fer­ent com­bi­na­tions of geom­e­try, pro­tec­tion, cat­a­lyst, and sub­strate for CNF to grow on,
  • tests long-term dura­bil­i­ty of the most promis­ing solutions,
  • devel­ops a high vol­ume pro­duc­tion con­cept, and
  • pro­duces a test series of CNF-MEA to be used in actu­al production.

Is your com­pa­ny a poten­tial part­ner? Con­tact us today, and let’s arrange a meet­ing to dis­cuss it further.

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