Periodic Reporting for period 2 - SUSTAINCELL (SUSTAINCELL: Durable and Sustainable component supply chain for high performance fuel cells and electrolysers)
Reporting period: 2024-07-01 to 2025-12-31
The SUSTAINCELL project aims at supporting the European industry in the development of the next generation electrolyser and fuel cell technologies (both low and high temperature) by developing a sustainable European supply chain of materials, components and cells, significantly less reliant on critical raw materials (CRM), with lower environmental footprint and costs, and higher performance and durability than existing technologies.
1. Progress on CRM reduction in HT electrolysers
• Innovative CRM‑free/lean materials (SOEL & PCCEL):
CEA: Al2O₃ and MgAl2O₄ added to Ni/YSZ cermet enable thinner electrodes with maintained strength; Ni‑3YSZ‑Al‑Mg composite shows major mechanical improvement vs. state‑of‑the‑art Ni‑3YSZ.
DLR: New perovskite LSCTN characterized as Ni/REE‑free alternative for Ni‑cermet; performance: 1.17 A/cm² @ 860 C, 1.2 V; 0.54 A/cm² @ 770 C, 1.2 V (Target 9 achieved).
DTU: CRM‑free SOEL air electrode based on LSF: Rp = 0.156 Ω·cm² @ 750C; degradation 3.2%/1000 h @ 750C, 0.5 A/cm² (Target 8 not yet achieved).
CEA: New La‑chromate perovskites with Sr→Ca substitution (LaSrCrMn, LaCaCrMn, LaCaCrFe). Best Rp = 8 Ω·cm² @ 750 C for LCCF without current collector.
SINTEF: CRM‑free PCCEL steam electrode using BZCY electrolyte + PBSCF electrode. Rp = 0.05 Ω·cm² @ 750 C (Target 8 achieved).
• Improved manufacturing protocols:
Magnetron sputtering (SINTEF/EPFL): SINTEF is developing a CeO2 barrier layer for PCCEL electrodes. CeO2 interlayer improves bonding and reduces ohmic resistance. EPFL developed dense CYO layers. Low deposition rate (500–700 nm) yields finer, denser layers. Ohmic resistance increases over time due to Sr segregation.
Tape casting (SINTEF): Proton‑conducting half‑cells with thin electrolytes (reduced from 30 µm to 18 µm). Electrolyte thickness and sintering temperature were optimized to obtain homogeneous, defect-free samples.
High‑throughput sputtering (CEA): Gradient zirconia→ceria interface to reduce resistivity. Optimized GDC thin films; EIS used to separate grain vs. grain‑boundary contributions. New setup under development for barrier‑layer resistance.
2. Progress on CRM reduction in LT electrolysers/fuel cells
• PFAS‑free PEM ionomers:
FZJ: PFAS‑free SFS‑28/OPBI membranes (ionic/covalent crosslinking), IEC optimized at 1.5 meq·g⁻¹.
SINTEF: 26 µm SFS‑28/OPBI membranes show PEMFC performance comparable to Nafion N212 (50 µm) in ASR, H2 permeation, cell performance, and durability.
• PFAS‑free/lean AEM ionomers:
FZJ: Polystyrene/OPBI AEMs with trimethylamine functionalization: conductivity 69 mS·cm⁻¹ @ 80 C, 90% RH; ASR 0.3 Ω·cm² @ 70 C, 1 M KOH (64 µm). Stable after 1000 h in 1 M KOH@85C.
• CRM‑free/lean electrocatalysts:
CNRS (Ni@N‑C HOR, AEMFC): Pyrolysis‑controlled shell composition correlates with HOR activity/stability. Optimized 1.5 h pyrolysis: 22% current loss after 4k cycles (−0.01→0.1 V vs RHE, 100 mV/s, 60 C, 0.1 M KOH). KPI achieved.
CNRS (Fe‑N‑C ORR, PEMFC): Two‑step pyrolysis with NH₄Cl in step 2 tunes microporosity and N‑basicity, improving ORR activity/durability.
DTU (Ni‑Mo HER, AEL/AEMEL): AI‑optimized electrodeposition yields 0.123 V overpotential @ 100 mA/cm², 80 C, 6 M KOH; ~0.187 V @ 10 mA/cm² (ECSA‑norm., RF=83, TS=70 mV/dec). Slight activity increase after 100 cycles. KPI achieved.
Tecnalia (Ni₁₋ₓFeₓOOH OER, AEMEL): Dip‑coated anodes on stainless steel (SS) and Ni felt: 283 mV (SS) and 260 mV (Ni) overpotential. NiFe8.9/0.1@SS shows lowest degradation (9%). Spray‑coated electrodes also tested in MEAs.
Tecnalia (NiMo & NiS HET, AEMEL): Dip‑coated catalysts on carbon GDL/Ni PTL. NiMo: 194 mV overpotential EoT. NiS: performance increases with S content (254 mV EoT).
DTU (Ir@IrOx/Nb‑TiO2 OER, PEMEL): Mass activity 174 mA mgIr⁻¹ @ 1.55 V (~3× commercial Alfa-Aesar (AA) IrO2); surface activity 1295 mA C⁻¹ (~10× AA IrO2). 1800 cycles (1.2–1.6 V) AST; 83% mass and 92% surface activity retained (AA IrO2: 43%/75%).
• Innovation in synthesis, manufacturing, & modelling:
DTU (Autonomous discovery): CatBot self‑driving lab for electrodeposition/testing. Explored ~10¹²‑size parameter space for Ni‑Mo HER; optimal coatings found within 30–40 experiments.
DLR (Flame spray pyrolysis): Pt‑embedded carbon‑network catalysts (Pt‑e‑Cn) with CRM‑free elements (Mn, Ni, Fe). Pt‑lean catalysts show 75% higher mass activity vs Pt/CHSA at 0.9 V.
DTU (Computational screening): Workflow screens Materials Project + GNoME (520k+ structures) for stability vs pH/potential, bandgap, and HHI to identify promising electrocatalysts.
CEA (MUSES/EuROPIUM modelling): PEMFC i‑V curves matched to MEAs with varying catalyst‑layer thickness and conditions. Model will guide optimization of ionomer/carbon ratio and distribution.
• Innovative CRM‑free/lean materials (SOEL & PCCEL):
CEA: Al2O₃ and MgAl2O₄ added to Ni/YSZ cermet enable thinner electrodes with maintained strength; Ni‑3YSZ‑Al‑Mg composite shows major mechanical improvement vs. state‑of‑the‑art Ni‑3YSZ.
DLR: New perovskite LSCTN characterized as Ni/REE‑free alternative for Ni‑cermet; performance: 1.17 A/cm² @ 860 C, 1.2 V; 0.54 A/cm² @ 770 C, 1.2 V (Target 9 achieved).
DTU: CRM‑free SOEL air electrode based on LSF: Rp = 0.156 Ω·cm² @ 750C; degradation 3.2%/1000 h @ 750C, 0.5 A/cm² (Target 8 not yet achieved).
CEA: New La‑chromate perovskites with Sr→Ca substitution (LaSrCrMn, LaCaCrMn, LaCaCrFe). Best Rp = 8 Ω·cm² @ 750 C for LCCF without current collector.
SINTEF: CRM‑free PCCEL steam electrode using BZCY electrolyte + PBSCF electrode. Rp = 0.05 Ω·cm² @ 750 C (Target 8 achieved).
• Improved manufacturing protocols:
Magnetron sputtering (SINTEF/EPFL): SINTEF is developing a CeO2 barrier layer for PCCEL electrodes. CeO2 interlayer improves bonding and reduces ohmic resistance. EPFL developed dense CYO layers. Low deposition rate (500–700 nm) yields finer, denser layers. Ohmic resistance increases over time due to Sr segregation.
Tape casting (SINTEF): Proton‑conducting half‑cells with thin electrolytes (reduced from 30 µm to 18 µm). Electrolyte thickness and sintering temperature were optimized to obtain homogeneous, defect-free samples.
High‑throughput sputtering (CEA): Gradient zirconia→ceria interface to reduce resistivity. Optimized GDC thin films; EIS used to separate grain vs. grain‑boundary contributions. New setup under development for barrier‑layer resistance.
2. Progress on CRM reduction in LT electrolysers/fuel cells
• PFAS‑free PEM ionomers:
FZJ: PFAS‑free SFS‑28/OPBI membranes (ionic/covalent crosslinking), IEC optimized at 1.5 meq·g⁻¹.
SINTEF: 26 µm SFS‑28/OPBI membranes show PEMFC performance comparable to Nafion N212 (50 µm) in ASR, H2 permeation, cell performance, and durability.
• PFAS‑free/lean AEM ionomers:
FZJ: Polystyrene/OPBI AEMs with trimethylamine functionalization: conductivity 69 mS·cm⁻¹ @ 80 C, 90% RH; ASR 0.3 Ω·cm² @ 70 C, 1 M KOH (64 µm). Stable after 1000 h in 1 M KOH@85C.
• CRM‑free/lean electrocatalysts:
CNRS (Ni@N‑C HOR, AEMFC): Pyrolysis‑controlled shell composition correlates with HOR activity/stability. Optimized 1.5 h pyrolysis: 22% current loss after 4k cycles (−0.01→0.1 V vs RHE, 100 mV/s, 60 C, 0.1 M KOH). KPI achieved.
CNRS (Fe‑N‑C ORR, PEMFC): Two‑step pyrolysis with NH₄Cl in step 2 tunes microporosity and N‑basicity, improving ORR activity/durability.
DTU (Ni‑Mo HER, AEL/AEMEL): AI‑optimized electrodeposition yields 0.123 V overpotential @ 100 mA/cm², 80 C, 6 M KOH; ~0.187 V @ 10 mA/cm² (ECSA‑norm., RF=83, TS=70 mV/dec). Slight activity increase after 100 cycles. KPI achieved.
Tecnalia (Ni₁₋ₓFeₓOOH OER, AEMEL): Dip‑coated anodes on stainless steel (SS) and Ni felt: 283 mV (SS) and 260 mV (Ni) overpotential. NiFe8.9/0.1@SS shows lowest degradation (9%). Spray‑coated electrodes also tested in MEAs.
Tecnalia (NiMo & NiS HET, AEMEL): Dip‑coated catalysts on carbon GDL/Ni PTL. NiMo: 194 mV overpotential EoT. NiS: performance increases with S content (254 mV EoT).
DTU (Ir@IrOx/Nb‑TiO2 OER, PEMEL): Mass activity 174 mA mgIr⁻¹ @ 1.55 V (~3× commercial Alfa-Aesar (AA) IrO2); surface activity 1295 mA C⁻¹ (~10× AA IrO2). 1800 cycles (1.2–1.6 V) AST; 83% mass and 92% surface activity retained (AA IrO2: 43%/75%).
• Innovation in synthesis, manufacturing, & modelling:
DTU (Autonomous discovery): CatBot self‑driving lab for electrodeposition/testing. Explored ~10¹²‑size parameter space for Ni‑Mo HER; optimal coatings found within 30–40 experiments.
DLR (Flame spray pyrolysis): Pt‑embedded carbon‑network catalysts (Pt‑e‑Cn) with CRM‑free elements (Mn, Ni, Fe). Pt‑lean catalysts show 75% higher mass activity vs Pt/CHSA at 0.9 V.
DTU (Computational screening): Workflow screens Materials Project + GNoME (520k+ structures) for stability vs pH/potential, bandgap, and HHI to identify promising electrocatalysts.
CEA (MUSES/EuROPIUM modelling): PEMFC i‑V curves matched to MEAs with varying catalyst‑layer thickness and conditions. Model will guide optimization of ionomer/carbon ratio and distribution.
- Supported Ir catalysts are synthesized at DTU by solid-state chemical synthesis. Best activity is obtained of 1.464 V at 100 mA mgIr-1 exceeding the commercial IrO2 catalysts. The stability is on par with the commercial IrO2 when tested at room temperature but lower than the commercial IrO2 catalysts at 60 °C. Results from In-operando XRD confirm that the bulk structures of the catalyst particles are stable throughout the accelerated stability tests.
- OER activity and stability of Ir doped into Zr2ON2; DTU found that Zr2ON2, both with and without Ir, has a high formation energy at OER conditions, which likely indicates that having N in the and surface layer of Zr2ON2 is unstable compared to having O corroborating the experimental findings in the literature. Possible stabilization and tuning of activity by additional dopants or additional O content is ongoing.
-OER catalysts at Tecnalia based on a soft-templating deposition method: 8 Ni-Fe formulations were characterized. Better performance was obtained with 283 mV at 100mAcm-2 after the CV stability tests for the sample with 1% Fe. NiFe catalysts were deposited on pure Ni PTL. Better performance is obtained with 251 mV at 100mAcm-2 for OER measured in the sample with 66% of Fe after the CV stability test. 5cm2 OER electrodes were manufactured with this method. Single cell with Pt as cathode material and Ni-Fe formulations were tested. Best performance was obtained with pure Ni at SS GDL and with NiFe (66%Fe) over Ni PTL with 1.9V at 1Acm-2.
- ORR Fe-N-C catalysts at CNRS: Work started by investigating if it is possible to use NH4Cl salt mixed with FeNC, instead of NH3 gas flow during the second pyrolysis step. Preliminary results show that similar high ORR activities can be obtained by using NH4Cl as NH3, which brings safety advantages during synthesis and also implies that less NH3 is consumed for activating the FeNC materials.
- ORR Pt-based electrocatalysts structure called carbon nanonetwork embedded Pt nanoparticles under development at DLR: Characterizations in RDE and in low Pt content PEMFC demonstrated approximately 4 times higher durability than commercial SoA Pt/C catalysts, without compromising activity.
Focus on developing innovative physical process for pre-concentrating Ni and Co to simplify the following hydrometallurgical steps. CEA developed a process allowing an efficient separation of these particles based on their settling properties after ball milling operation.
Two public deliverables present an overview of the different hydrogen-fed FC and EL technologiesof SUSTAINCELL and reports the inventory and quantification of CRM and describes the main hotspots of environmental impacts for five selected state-of-art technologies.
- OER activity and stability of Ir doped into Zr2ON2; DTU found that Zr2ON2, both with and without Ir, has a high formation energy at OER conditions, which likely indicates that having N in the and surface layer of Zr2ON2 is unstable compared to having O corroborating the experimental findings in the literature. Possible stabilization and tuning of activity by additional dopants or additional O content is ongoing.
-OER catalysts at Tecnalia based on a soft-templating deposition method: 8 Ni-Fe formulations were characterized. Better performance was obtained with 283 mV at 100mAcm-2 after the CV stability tests for the sample with 1% Fe. NiFe catalysts were deposited on pure Ni PTL. Better performance is obtained with 251 mV at 100mAcm-2 for OER measured in the sample with 66% of Fe after the CV stability test. 5cm2 OER electrodes were manufactured with this method. Single cell with Pt as cathode material and Ni-Fe formulations were tested. Best performance was obtained with pure Ni at SS GDL and with NiFe (66%Fe) over Ni PTL with 1.9V at 1Acm-2.
- ORR Fe-N-C catalysts at CNRS: Work started by investigating if it is possible to use NH4Cl salt mixed with FeNC, instead of NH3 gas flow during the second pyrolysis step. Preliminary results show that similar high ORR activities can be obtained by using NH4Cl as NH3, which brings safety advantages during synthesis and also implies that less NH3 is consumed for activating the FeNC materials.
- ORR Pt-based electrocatalysts structure called carbon nanonetwork embedded Pt nanoparticles under development at DLR: Characterizations in RDE and in low Pt content PEMFC demonstrated approximately 4 times higher durability than commercial SoA Pt/C catalysts, without compromising activity.
Focus on developing innovative physical process for pre-concentrating Ni and Co to simplify the following hydrometallurgical steps. CEA developed a process allowing an efficient separation of these particles based on their settling properties after ball milling operation.
Two public deliverables present an overview of the different hydrogen-fed FC and EL technologiesof SUSTAINCELL and reports the inventory and quantification of CRM and describes the main hotspots of environmental impacts for five selected state-of-art technologies.