EFCF 2025: Low-Temp. Fuel Cells, Elec olyse s & H2 P ocessing 1 – 4 July 2025, Luce ne Swi ze land
h ps://doi.o g/10.5281/zenodo.17244125 A0812 Page 1/6
A0812
Oxida ion o Po ous T anspo Laye s in Anion
Exchange Memb ane Wa e Elec olysis wi h Alkaline
and Pu e Wa e Feed
Luis Hagne (1,2), Se e in Vie a h (1,2), Susanne Koch (1,2)
(1) Elec ochemical Ene gy Sys ems, IMTEK - Depa men o Mic osys ems Enginee ing,
Uni e si ä F eibu g/Ge many;
(2) Hahn-Schicka d, F eibu g/Ge many;
*Con ac co esponding au ho s: www.EFCF.com/Con ac Reques
Abs ac
In anion-exchange memb ane wa e elec olysis (AEMWE), po ous anspo laye s (PTLs)
can also be applied as po ous anspo elec odes (PTEs), i.e. wi h no addi ional ca alys
laye be ween memb ane and PTL. Especially in alkaline condi ions, PTEs made om
s ainless s eel ha e shown high ac i i y and du abili y, i aling ha o sys ems wi h dedica ed
ca alys laye s, such as NiFe-hyd oxide powde based ca alys laye s.[1]
The aim o his s udy is o in es iga e elec ode ac i a ion o e ime, ela ing su ace
oxida ion and Fe anspo o cell ol age inc ease. Di e en ibe elec odes a e in es iga ed,
measu ing pola iza ion cu es up o 4 Acm-2 and deg ada ion a 1 Acm-2 in 1.0 M KOH a
60 °C. All s ainless s eel cells show simila deg ada ion p o iles, wi h deg ada ion a es om
200 – 400 µVh-1 in he las 50 h o es ing. A e disassembly, me al-con aining pa icles a e
obse ed in he ca hode-memb ane in e ace. SEM-EDX con i ms Fe as he highes mass
ac ion o hese pa icles (e).
Figu e 1: Single cell measu emen s o s ainless s eel ibe elec odes (PTEs). Elec odes we e es ed
a 60 °C in 1.0 M KOH up o cu en s o 4 Acm-2 in pola iza ion cu es (a) and o 100 h in du abili y
es ing a 1 Acm-2. The oxida ion o hese elec odes depending on ope a ing po en ial leads o
dissolu ion o Fe and o he me als con ained in he s eel (c), ha ge deposi ed in he
ca hode/memb ane in e ace (d), (e).
EFCF 2025: Low-Temp. Fuel Cells, Elec olyse s & H2 P ocessing 1 – 4 July 2025, Luce ne Swi ze land
h ps://doi.o g/10.5281/zenodo.17244125 A0812 Page 2/6
In oduc ion
Anion-exchange memb ane wa e elec olysis (AEMWE) is a p omising echnology o
hyd ogen p oduc ion, le e aging he bene i s o low-cos ma e ials o ca alys s and
componen s and u he e icien a iable load sys em ope a ion. The alkaline media, o en
implemen ed by using KOH as a suppo ing elec oly e, enables he use o ansi ion-me al
based ca alys s (e.g. based on Ni, Fe, Co), educing aw ma e ials cos signi ican ly by
o de s o magni ude compa ed o I /Ru-based anode ca alys s used in p o on-exchange
memb ane wa e elec olysis (PEMWE). NiFe-oxyhyd oxides (NiFe-OOH) ha e shown o be
highly ac i e ma e ials ha can be syn hesized as powde s o g own di ec ly on subs a es.
Howe e , elec odes p epa ed by hese me hods using a po ous- anspo -laye (PTL) wi h
dedica ed ca alys laye (powde -based o sel -suppo ed), ha e limi ed mass ac i i y, owed
o a low elec ical conduc i i y o hese ypes o ca alys s, and because o high-wa e up ake
binde s a ec ing mass- anspo and p obably pa icle sepa a ion[2]. Also, Ni-based
oxyhyd oxides su e om a “cha ge- apping” e ec du ing po en ial cycling, due o di e en
elec ical conduc i i y o he in ol ed Ni-species.[3]
In con as , s ainless s eel ibe elec odes p o ide a simple sys em a chi ec u e, combining
PTL and ca alys laye in a po ous- anspo elec ode (PTE). The de ined in e ace be ween
PTE and memb ane u he simpli ies he s udy o hese sys ems. Using a suppo ing
elec oly e o 1 M KOH enables a high olume ac i i y o he PTE, whe eas in pu e wa e
ope a ion an addi ional Ionome coa ing ensu es OH- anspo . S ainless s eel elec odes
ha e appealing quali ies o sys em a chi ec u e, cos and ac i i y o AEMWE sys ems.
Mul iple s udies conclude ha he ac i a ion o Fe-con aining elec odes changes su ace-
composi ion o he ma e ial, in ol ing leaching o dominan ly Fe and o he me als such as
C and Mo[4]. In gene al, he s abili y o Fe-con aining elec odes is deba ed.[5] A s able
ope a ion a high cu en densi ies has been epo ed, bu he au ho s s ill de ec ed low
amoun s o Fe species deposi ed on he ca hode[6]. Also, he e ec o ca hode (de)ac i a ion
o he used P /C elec odes is no p ecisely known. In alkaline elec olysis (AWE), deposi ion
o Fe on he ca hode was ound o inc ease ca hode ac i i y mainly because he deposi ed
Fe inc eased he su ace a ea o he ca hode.[7] F om chlo akali echnology, so-called
“poison- esis an ” P Ru ca hodes ha e been de eloped.[8] The enla gemen o su ace a ea
and deposi ion modi ica ion made elec ode pe o mance less suscep ible o deac i a ion by
deposi ed Fe. E ec s on he memb ane ma e ial and pe o mance ela ed o anspo o Fe
species h ough he memb ane ha e no been shown on an AEMWE cell le el ye . Howe e ,
i could be possible ha mig a ion o Fe-species om anode o ca hode damages he
memb ane in a Fen on- ype o eac ion.[9]
1. Scien i ic App oach
Di e en ypes o s ainless s eel elec odes we e employed o AEMWE ope a ion using a
suppo ing elec oly e o KOH in di e en concen a ion anges om 1.0 M o 10 mM. Cell
ol age o e ime was moni o ed a 1 Acm-2 using EIS. Fibe diame e s we e co ela ed o
elec ode capaci ance and ac i i y.
The co osion beha io o he PTE led o Fe and C leaching, and deposi ion o hese
elemen s in he ca hode/memb ane in e ace. Fo isualiza ion and elemen al analysis, X-
ay Fluo escence mapping (XRF) and SEM-EDX we e used.
EFCF 2025: Low-Temp. Fuel Cells, Elec olyse s & H2 P ocessing 1 – 4 July 2025, Luce ne Swi ze land
h ps://doi.o g/10.5281/zenodo.17244125 A0812 Page 3/6
2. Expe imen s/Calcula ions/Simula ions
Ma e ials
S ainless s eel el s (SS-62/410, SS-71/260, SS-72/300, Bekipo 300 µm) we e pu chased
om Bekae . Main p ope ies o he s eel ibe s used a e lis ed in Table 1. F eudenbe g
H24C5 ca bon pape wi h mic opo ous laye (MPL) was used as ca hode GDL wi h P /C (50
w %, Elys 5050) ca alys . Anion-exchange memb anes (Pipe Ion 40) and Ionome (Pipe Ion
A, 5% in E OH) we e supplied by Ve sogen and FuelCellS o e. Po assium hyd oxide (KOH)
pelle s (85 %) was pu chased om Ca l Ro h GmbH + Co. KG.
Ca hode gas-di usion elec odes
P /C ca hode gas di usion elec odes we e sp ay coa ed using an ul asonic sp ay coa e
(SNR 300, Sonocell). Fo he sp aycoa ing ink, P /C ca alys (150 mg) was mixed wi h wa e
(2 g), Isop opanol (7 g) and Pipe Ion A (0.8 g, 5% in E hanol), Ionome :Ca bon a io 0.2.
The ink was sp ayed on F eudenbe g H24C5 gas di usion laye , wi h a me al loading o
0.55 mg/cm2.
Elec ochemical measu emen s
P io o es ing, Pipe Ion A 40 µm memb ane and ca hode GDE we e imme sed in 1 M KOH
o a leas 1 h. Cells we e assembled using PTFE gaske s wi h 5 cm2 ac i e a ea o a ying
hickness o ensu e ca. 40 % ca hode comp ession. The anode hickness o he s ainless
s eel was ma ched o ha e no anode comp ession. Elec oly e was hea ed o 60 °C and
ci cula ed wi h 50 mLmin-1. A BioLogic VSP-300 po en ios a wi h wo 10 A/5 V boos e s was
used o moni o cell ol age. Pola iza ion cu es we e measu ed holding each cu en o 40
s plus 30 s o GEIS measu emen (500 kHz o 100 Hz, ampli ude 5%, no exceeding 50
mAcm-2). Fo a b eak-in o he cell, an addi ional pola iza ion cu e as desc ibed abo e was
measu ed ollowing EIS a 500 and 1000 mAcm-2. The elec ode capaci ance was
de e mined by CV om 0.4 V o 0.5 V using scan a es om 200, 150, 100, 75, 50 and
25 mVs-1. A e his, he inal pola iza ion cu e used o e alua ion was aken, ollowed by
a cu en hold o 1 Acm-2 o a ying ime. The cha ac e iza ion o pola iza ion cu e,
capaci ance de e mina ion and GEIS we e epea ed a e he cu en hold. Finally, he cell
was checked o elec ical sho s a 1.2 V o 5 min.
Table 1: P ope ies o s ainless s eel ibe PTEs.
PTE Type
Po osi y
Thickness
Laye ype
ibe diame e / µm
SS-62/410
62 %
410 µm
dual
3
SS-78/300
78 %
300 µm
dual
5
SS-71/260
71 %
260 µm
single
5
Bekipo 300 µm
n.A.
300 µm
single
10
3. Resul s
The esul s o single cell es ing a e shown in Figu e 2. All s eel PTEs show high ac i i y in
he anges o 2.0 o 2.1 V a a cu en o 4 Acm-2 (Fig.2a). Pola iza ion cu es co ec ed by
ohmic d op (do ed lines) show ha he mos ac i e a e SS-62/410 and SS-B-300. The cells
show an ac i a ion phase o ca. 30 h un il eaching a linea deg ada ion a e o 200 o
400 µVh-1 (Fig. 2b). Since he PTEs a e made o he same 316L s ainless s eel (composi ion
shown in Fig.2c), he imp o ed kine ic ac i i y can be ela ed o he inc eased su ace a ea
o elec odes. O all samples, SS-62/410 has he smalles ibe diame e in con ac wi h he
memb ane and suppo ing elec oly e, leading o a high ECSA (Fig.3a). To con i m his, he
elec ode capaci ance was measu ed using cyclic ol amme y (CV) a a ious scan a es
(Fig.2d), ex ac ing he ne cu en densi ies o cha ge and discha ge (Fig.1e). SS62/410
EFCF 2025: Low-Temp. Fuel Cells, Elec olyse s & H2 P ocessing 1 – 4 July 2025, Luce ne Swi ze land
h ps://doi.o g/10.5281/zenodo.17244125 A0812 Page 4/6
shows he highes capaci ance o 4.0±0.1 mFcm-2 measu ed in a h ee-elec ode cell se up
(Fig.2 ), as well as in he single cell es . As he bes pe o ming ma e ial in pola iza ion
cu es and cu en holds, u he cell expe imen s we e conduc ed using his SS62/410 ype
o PTE. O he easons o be e pe o mance could be imp o ed mass anspo and bubble
managemen due o he dual laye con igu a ion o he PTE. A coa se wo en mesh a he
backside c ea es addi ional olume be ween low ield lands and PTE, c ea ing mo e oom
o gas anspo .
Figu e 2: AEMWE single cell es s wi h a ious s ainless s eel anode PTEs. Pola iza ion cu es
shown (a), du abili y es s a 1 Acm-2 in (b). S ainless s eel composi ion as de e mined by XRF (c),
and capaci ance measu emen s by CV d) – ( ). Tes s we e conduc ed a 60 °C wi h a 0.5 mgcm-2
P /C on ca bon pape ca hode.
A e cell es ing, disassembled cells we e imaged using SEM. As a e e ence, a cell was
assembled as no mal, wi hou elec ochemical es ing, and hea ed o 1h o 60 °C. This
e e ence cell showed s ong p o usion o he s eel ibe s on he anode side (Fig.3c),
especially in he comp essed egion, whe e he low ield land exe ed he mos o ce. On he
opposi e side, he ca hode acing a homogeneous la mic opo ous laye o he GDL did no
su e om pe manen de o ma ion (Fig.3d). A e 100 h o es ing and disassembly, black-
b own pa icles we e isible on bo h he memb ane and ca hode side in he
ca hode/memb ane in e ace. SEM-EDX showed Fe species being he highes mass ac ion
o hese pa icles, hus con i ming ha Fe species deposi as a esul o anode PTE co osion
(Fig.3e/ ).
EFCF 2025: Low-Temp. Fuel Cells, Elec olyse s & H2 P ocessing 1 – 4 July 2025, Luce ne Swi ze land
h ps://doi.o g/10.5281/zenodo.17244125 A0812 Page 5/6
Figu e 3: SEM images o SS-62/410 ibe el and memb ane su aces a e es ing. The ine mesh
ibe s o SS-62/410 shown in a) wi h a magni ica ion o he highligh ed egion in (b) p o ude he
memb ane, leading o g oo es isible in d y s a e (c). The ca hode- acing side o he memb ane
shows islands o deposi ed Fe and de ached P /C pa icles om he ca hode (e), as de e mined by
EDX ( ).
Re e ences
[1] A. W. T icke , J. K. Lee, J. R. Shin, N. Danilo ic, A. Z. Webe , X. Peng, Jou nal o
Powe Sou ces 2023, 567, 232967.
[2] a) S. S. Jeon, P. W. Kang, M. Klingenho , H. Lee, F. Dionigi, P. S asse , ACS
ca alysis 2023, 13, 1186; b) M. E. K eide , H. Yu, L. Osmie i, M. R. Pa imuha, K. S.
Ree es, D. H. Ma in, R. T. Hannagan, E. K. Volk, T. F. Ja amillo, J. L. Young e al.,
ACS ca alysis 2024, 14, 10806.
[3] a) D. A. Co igan, S. L. Knigh , J. Elec ochem. Soc. 1989, 136, 613; b) M. B. S e ens,
L. J. Enman, A. S. Ba chello , M. R. Cosby, A. E. Vise, C. D. M. T ang, S. W.
Boe che , Chem. Ma e . 2017, 29, 120.
[4] a) Suhas Nuggehalli Sampa hkuma , T.B. Fe iday, Hugh Middle on, Jan Van he le
2023; b) S. Han, Jaeyune Ryu, Jeyong Yoon, Chemical Enginee ing Jou nal 2024; c)
N. Todo oki, T. Wadayama, Jou nal o Powe Sou ces 2024, 613, 234854; d) T.
Fe iday, Suhas Nuggehalli Sampa hkuma , Mouni D. Mensi, P. H. Middle on, J. Van
He le, M. Kolhe, ACS Applied Ma e ials and In e aces 2024.
[5] a) And ew R. Mo z, Dongguo Li, Alex Keane, Luis Del in Man iquez, Eun Joo Pa k,
Sandip Mau ya, Hoon Chung, Hoon T Chung, Cy Fujimo o, Jongyeob Jeon e al.,
Jou nal o Ma e ials Chemis y 2021; b) Vale ia Nicolosi, D. V. Tyndall, Michael C aig,
Lee Gannon, Co mac McGuinness, Niall McE oy, Ahin Roy, Max Ga cía‐Melcho ,
Michelle P. B owne, Jou nal o Ma e ials Chemis y A 2023.
[6] A. W. T icke , T. Y. E ug ul, J. K. Lee, J. R. Shin, W. Choi, D. I. Kushne , G. Wang, J.
Lang, I. V. Zenyuk, A. Z. Webe e al., Ad anced Ene gy Ma e ials 2024, 14.
EFCF 2025: Low-Temp. Fuel Cells, Elec olyse s & H2 P ocessing 1 – 4 July 2025, Luce ne Swi ze land
h ps://doi.o g/10.5281/zenodo.17244125 A0812 Page 6/6
[7] M. Demni z, Y. M. Lamas, R. L. Ga cia Ba os, A. de Leeuw den Bou e , J. an de
Schaa , M. Theodo us de G oo , iScience 2024, 27, 108695.
[8] D. S. Came on, R. L. Phillips, P. M. Willis in Mode n Chlo -Alkali Technology (Eds.: N.
M. P ou , J. S. Moo house), Sp inge Ne he lands, Do d ech , 1989, pp. 95–107.
[9] A. F. S ae z, M. an Leeuwen, T. P iamushko, T. Saa kamp, B. End ődi, N.
Plankens eine , M. Jobbagy, S. Pahla an, M. J. W. Blom, C. Janáky e al.,
Angewand e Chemie (In e na ional ed. in English) 2024, 63, e202306503.
Keywo ds: EFCF2025, H2, LowTemp. Fuel Cells & Elec olyse s, AEM, Deg ada ion,
S ainless s eel elec odes, Elec ode oxida ion, Elec ode co osion
Rema k: This wo k is licensed unde C ea i e Commons A ibu ion 4.0 In e na ional
