Smoltek’s groundbreaking PTE technology earns expert recognition

Smol­tek has taken a stra­tegic step by invit­ing Dr. Felix N. Büchi, an inde­pend­ent expert in pro­ton exchange mem­brane (PEM) tech­no­lo­gies, to review Smol­tek Hydrogen’s Por­ous Trans­port Elec­trode (PTE) tech­no­logy. In his eval­u­ation, Dr. Büchi recog­nizes that ”Smol­tek elec­trodes are a very inter­est­ing devel­op­ment for the pro­duc­tion of low iridi­um load­ing elec­trodes for PEM elec­tro­lyz­ers.” His com­pre­hens­ive ana­lys­is provides valu­able insights for fur­ther devel­op­ment. Let’s delve into the details of this excit­ing eval­u­ation and what it means for Smoltek’s future.

Who is Dr. Felix N. Büchi?

You might be won­der­ing who Dr. Felix N. Büchi is and why his opin­ion car­ries such weight. As a prom­in­ent Swiss sci­ent­ist spe­cial­iz­ing in elec­tro­chem­ic­al energy con­ver­sion and stor­age, Dr. Büchi is at the fore­front of fuel cell tech­no­logy and elec­tro­lyz­er development.

As Group Head at the Elec­tro­chem­istry Labor­at­ory at Switzerland’s pres­ti­gi­ous Paul Scher­rer Insti­tute (PSI), Dr. Büchi focuses on advan­cing PEM fuel cells and PEM elec­tro­lyz­ers. His expert­ise is par­tic­u­larly rel­ev­ant in char­ac­ter­iz­ing and eval­u­at­ing por­ous mater­i­als for these applic­a­tions. His pion­eer­ing work with X‑ray ima­ging under oper­ando con­di­tions has revo­lu­tion­ized the under­stand­ing of PEM devices’ mass trans­port and two-phase flow, lead­ing to approx­im­ately 50 ded­ic­ated papers since 2009.

With a Ph.D. in Fun­da­ment­al Elec­tro­chem­istry from the Uni­ver­sity of Bern and exper­i­ence from respec­ted insti­tu­tions like Texas A&M Uni­ver­sity, Dr. Büchi is recog­nized glob­ally for his expert­ise in poly­mer elec­tro­lytes and elec­tro­chem­ic­al systems.

The Büchi Report

Dr. Büchi’s assign­ment was to eval­u­ate Smol­tek Hydrogen’s PTE tech­no­logy. The res­ult­ing doc­u­ment, ”The Büchi Report,” provides an in-depth ana­lys­is of the technology’s per­form­ance and areas for fur­ther optimization.

While the full report con­tains con­fid­en­tial busi­ness inform­a­tion, we’re excited to share key high­lights with you. These insights demon­strate how Smoltek’s innov­a­tion addresses a crit­ic­al chal­lenge in the PEM elec­tro­lyz­er industry –  the press­ing issue of iridi­um scarcity that threatens to con­strain the industry’s growth.

The iridium challenge

The num­bers tell a strong  story: The green hydro­gen industry will need 30 tons of iridi­um annu­ally by 2030, while glob­al pro­duc­tion capa­city is lim­ited to 9 tons annu­ally. With cur­rent iridi­um prices around 150,000 EUR per kilo­gram, and mar­ket ana­lysts pro­ject­ing prices to reach 700,000 EUR per kilo­gram by 2030 due to the sup­ply-demand gap, redu­cing iridi­um usage becomes cru­cial for com­mer­cial viab­il­ity. With our tech­no­logy, iridi­um con­sump­tion is reduced by 95% com­pared to cur­rent levels.

Understanding PEM electrolyzers

The reduc­tion of iridi­um load is pos­sible  because of our fun­da­ment­al rethink­ing of elec­trode design. To under­stand our approach, let’s look at the basic struc­ture of a PEM electrolyzer.

It has two elec­trodes sep­ar­ated by a thin pro­ton exchange mem­brane (PEM). At one elec­trode, called the anode, the sur­face of the titani­um por­ous trans­port lay­er (PTL) pressed against the mem­brane must be coated with iridi­um. This extremely rare and expens­ive met­al acts as a cata­lyst to make the reac­tion hap­pen. This is where Smoltek’s break­through innov­a­tion comes in.

Our approach revolves around the innov­at­ive use of car­bon nan­ofibers (CNF): We grow these CNFs dir­ectly on the titani­um sur­face that faces the mem­brane, cre­at­ing a struc­ture that mul­ti­plies the sur­face area by 10–30 times. This greatly enlarged sur­face area means we can spread out and util­ize the iridi­um cata­lyst much more effi­ciently – achiev­ing the same per­form­ance with much less of the pre­cious metal.

We call the com­plete assembly – a titani­um PTL with iridi­um coated CNFs on the mem­brane-facing sur­face – a Por­ous Trans­port Elec­trode (PTE). This integ­rated approach rep­res­ents a fun­da­ment­al shift from tra­di­tion­al elec­trode design, com­bin­ing struc­tur­al sup­port, increased sur­face area, and cata­lyst func­tion­al­ity in a single com­pon­ent. The tech­no­logy is strongly pro­tec­ted by pat­ents cov­er­ing key aspects of the design and man­u­fac­tur­ing process..

Smoltek’s innovative solution

The effect­ive­ness of this approach has been proven in extens­ive test­ing. By apply­ing iridi­um to our CNF-enhanced PTL using a pro­pri­et­ary pro­cess, we’ve achieved remark­able res­ults in redu­cing iridi­um loading.

Dr. Büchi eval­u­ated our elec­trodes with 0.2 mg/​cm² of iridi­um, which already rep­res­ents a sig­ni­fic­ant reduc­tion from the up to 2 mg/​cm² used in tra­di­tion­al electrodes.

Build­ing on these prom­ising res­ults, our devel­op­ment work con­tin­ues toward our tar­get of  0.1 mg/​cm², which would mark a break­through in iridi­um util­iz­a­tion efficiency.

Optimizing for durability

The car­bon nan­ofibers in Smoltek’s design require pro­tec­tion against the harsh, highly oxid­iz­ing envir­on­ment at the anode. To pre­vent degrad­a­tion, we apply a pro­tect­ive lay­er of plat­in­um. Dr. Büchi con­firms that this pro­tect­ive lay­er is rel­ev­ant for our approach.

Ensur­ing long-term dur­ab­il­ity remains a top pri­or­ity. We’re com­mit­ted to extens­ive test­ing under real-world oper­at­ing con­di­tions to veri­fy that our efforts nev­er com­prom­ise the reli­ab­il­ity and per­form­ance of our electrodes.

Technical advantages

Dr. Büchi’s ana­lys­is high­lights sev­er­al key strengths of our approach:

The examined iridi­um load­ing (0.2 mg/​cm²) demon­strates sig­ni­fic­ant eco­nom­ic poten­tial, par­tic­u­larly con­sid­er­ing iridium’s high cost and lim­ited availability.

The CNF-enhanced sur­face area, which is 10–30 times lar­ger than the ori­gin­al PTL mem­brane-facing sur­face, enables more effi­cient cata­lyst util­iz­a­tion – a key factor in achiev­ing high per­form­ance with reduced mater­i­al use.

Ini­tial test­ing con­firms remark­able ini­tial res­ults, achiev­ing 2.5 A/​cm² at 2V at 80 °C – a per­form­ance that, in his words, ”matches the state of the art.”

This shows that our unique approach to elec­trode design can deliv­er industry-com­pet­it­ive per­form­ance while using sig­ni­fic­antly less iridium.

Dr. Büchi’s assessment

In his over­all assess­ment Dr Büchi con­cludes: “Smoltek’s elec­trodes are a very inter­est­ing devel­op­ment for the pro­duc­tion of low iridi­um load­ing elec­trodes for PEM elec­tro­lyz­ers.” Accord­ing to Dr. Büchi, the tech­no­logy makes it pos­sible to cre­ate anodes with a greatly enlarged sur­face area while using min­im­al amounts of iridi­um cata­lyst, all integ­rated dir­ectly onto the por­ous trans­port layer.

His eval­u­ation included both examin­ing the elec­trode by itself (“ex-situ char­ac­ter­iz­a­tion”) and test­ing it under real oper­at­ing conditions.

He notes that “the ex-situ char­ac­ter­iz­a­tion of the elec­trodes shows that the aspired goals with high sur­face and low homo­gen­eous spe­cif­ic iridi­um load­ing can be realized.” 

While these ini­tial eval­u­ations are prom­ising, the most com­pel­ling res­ults come from real-world test­ing. Dr. Büchi examined the elec­trode’s per­form­ance when integ­rated into a com­plete elec­tro­lyz­er cell, where it worked togeth­er with a mem­brane and cath­ode to pro­duce hydro­gen under actu­al oper­at­ing conditions.

Performance insights

Earli­er this year, Smol­tek achieved a sig­ni­fic­ant mile­stone by suc­cess­fully oper­at­ing a PEM elec­tro­lyz­er cell for 1,000 hours using only 0.2 mg/​cm² of iridi­um cata­lyst. Dr. Büchi’s thor­ough ana­lys­is of this dur­ab­il­ity test has now provided valu­able insights into both the tech­no­logy’s cap­ab­il­it­ies and its path forward.

In his assess­ment, he notes: “The char­ac­ter­iz­a­tion in PEM elec­tro­lys­is cells shows that the Smol­tek elec­trodes give a very good per­form­ance at begin of life. Though, at the time, a deac­tiv­a­tion occurs in the first 10 hours of oper­a­tion.  There are hypo­theses on the mech­an­ism, but none is proven.”

Let’s break this down: The ini­tial per­form­ance was excel­lent – exactly what we were look­ing for. How­ever, dur­ing the first 10 hours of oper­a­tion, we observed a decrease in per­form­ance. While the elec­trode con­tin­ued to pro­duce the desired hydro­gen out­put through­out the remain­ing 990 hours, it required slightly more elec­tric­al power than optimal.

The cause of this per­form­ance drop had puzzled our team until Dr. Büchi’s eval­u­ation. His insights provided a likely explan­a­tion for the reduced mem­brane con­tact area and, more import­antly, offered clear path­ways for improve­ment. Based on his recom­mend­a­tions, we’re imple­ment­ing sev­er­al enhance­ments for our next dur­ab­il­ity test:

• Strength­en­ing the bond between fibers and membrane
• Modi­fy­ing the elec­trode configuration
• Upgrad­ing to more soph­ist­ic­ated test equipment

With these improve­ments in place, we’re con­fid­ent in our path for­ward. Our goal remains clear: demon­strat­ing that our PTE tech­no­logy can match industry-stand­ard per­form­ance while using sig­ni­fic­antly less iridium.

What does this mean for Smoltek’s future?

Dr. Büchi’s report rein­forces our con­fid­ence in the fun­da­ment­al approach of our PTE tech­no­logy. His inde­pend­ent assess­ment con­firms that our innov­at­ive meth­od for redu­cing iridi­um load­ing while main­tain­ing high per­form­ance addresses a crit­ic­al industry chal­lenge. The report also provides valu­able guid­ance for our con­tin­ued devel­op­ment work.

The path to com­mer­cial­iz­a­tion in deep tech often requires care­ful atten­tion to detail and sys­tem­at­ic eval­u­ation. Each mile­stone we achieve – includ­ing this thor­ough extern­al review – brings us closer to our goal of enabling more effi­cient and sus­tain­able hydro­gen pro­duc­tion. We’re par­tic­u­larly encour­aged by Dr. Büchi’s con­firm­a­tion that our approach to redu­cing iridi­um usage shows prom­ise, as this addresses one of the most sig­ni­fic­ant bar­ri­ers to scal­ing up green hydro­gen production.

Your thoughts matter

As share­hold­ers and stake­hold­ers in Smoltek’s jour­ney, your per­spect­ive is invaluable:

• How do you see this review impact­ing Smoltek’s pos­i­tion in the green hydro­gen market?
• What aspects of Dr. Büchi’s report do you find most encouraging?
• How can we bet­ter com­mu­nic­ate our pro­gress and mile­stones as we work towards commercialization?

Join the dis­cus­sion in the com­ments sec­tion of our Linked­In post about this art­icle. Your insights help shape our com­mu­nic­a­tion strategy and rein­force the value of patience in devel­op­ing trans­form­at­ive tech­no­lo­gies. Togeth­er, we’re build­ing a found­a­tion for a more sus­tain­able future.