Alkaline electrolysers with enhanced durability

Project Information

ENDURE

Grant agreement ID: 101137925

DOI

10.3030/101137925

EC signature date 5 December 2023

Start date 1 January 2024

End date 31 December 2026

Funded under

• Climate, Energy and Mobility

Total cost

€ 2 492 868,75

EU contribution

€ 2 492 868,75

Coordinated by

OU STARGATE HYDROGEN SOLUTIONS
Estonia

Periodic Reporting for period 1 - ENDURE (Alkaline electrolysers with enhanced durability)

Reporting period: 2024-01-01 to 2025-06-30

Summary of the context and overall objectives of the project

The ENDURE project aims to improve the performance and durability of alkaline electrolysers, supporting the EU’s strategic objectives for renewable hydrogen production. Current systems typically operate above 2 V/cell (>54 kWh/kg) and suffer from degradation that increases lifetime energy use and requires oversizing of balance-of-plant components, raising both operating and capital costs. While 3D-structured electrodes can achieve performance close to proton exchange membrane (PEM) systems, the long-term stability of platinum-group-metal (PGM)-free designs remains largely unproven. ENDURE will deliver a PGM-free alkaline electrolyser stack with the following targets:

Electricity consumption <48 kWh/kg
Current density >1.25 A/cm²
Degradation rate <0.1%/1,000 h
CAPEX 150 €/kW, O&M cost 35 €/(kg/d)/year
Critical raw material use: 0 mg/W

Key innovations include:

Development of 3D-structured, laterally graded, flow-engineered monolithic porous transport electrodes (PTEs)
Multi-scale computational fluid dynamics (CFD) modelling with advanced X-ray tomography
Scalable fabrication of high-performance PGM-free electrocatalysts
Stack-level upgrades (improved gaskets, novel diaphragms, CFD-engineered components)
Harmonised test protocols and accelerated ageing procedures

By cutting degradation, ENDURE will reduce operating costs and allow smaller balance-of-plant designs, lowering the levelised cost of hydrogen (LCOH) and strengthening the EU’s position in renewable hydrogen technologies by 2026.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

WP1 – Establishing methods and baseline
A harmonised test protocol for ENDURE was finalised and adopted. The baseline alkaline stack was developed by Stargate Hydrogen, shipped to FHa, and integrated into their test bench. The setup was upgraded with an electrochemical impedance spectroscopy (EIS) device and the necessary modifications to the test rig were completed to accommodate both the stack and the EIS system.

WP2 – Electrode development and scale-up
Screen-printed and doctor blade–coated Ni foams were characterised via X-ray tomography and assessed for flow sensitivity, showing outstanding bubble evacuation for the second-generation porous transport electrodes (PTEs). A synthesis route for nickel–molybdenum–coated electrodes was developed, and electrochemical testing under industrial conditions demonstrated very high activity and good stability for both a nickel–molybdenum HER catalyst and a nitrogen-doped nickel–molybdenum OER catalyst.

WP3 – Cell and stack development
Microscale modelling results (Darcy–Forchheimer parameters) were integrated into a macroscale model combining electrochemistry and dual-phase flow at stack level. Five diaphragm materials were tested. Six gasket materials were identified and are undergoing testing. An automated gasket installation procedure was developed to improve assembly precision and repeatability.

WP4 – Testing and validation
A comprehensive review of degradation phenomena and stressors in alkaline electrolysis was completed, supported by literature studies and consortium input. Seven accelerated stress test methods were defined and applied to Raney–Nickel cathodes, revealing reverse currents as the dominant degradation factor. Initial 100 cm² stack testing provided insights into electrical resistance across different PTL configurations, identifying oxide formation at anode PTL–bipolar plate interfaces as a major contributor. Pressure variation between 5 and 15 bar showed no measurable impact on cell performance.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

WP2 has advanced alkaline water electrolysis (AWE) with a new generation of 3D, flow-engineered porous transport electrodes (PTEs) showing excellent bubble removal, enhanced mass transport, and reduced cell voltage at high current density, outperforming conventional flat electrodes.
Non-PGM, non-CRM electrocatalysts were developed for HER and OER. Ni–Mo HER and N-doped Ni–Mo OER catalysts achieved overpotentials <−150 mV and ~250 mV at ±1 A/cm² under industrial conditions, demonstrating competitive performance.
The optimised PTEs with integrated catalysts are being scaled for stack integration, targeting <1.95 V at >1.25 A/cm², energy consumption <47 kWh/kg H2, and lower CAPEX and OPEX. The work delivers a scalable, high-performance, low-cost solution for green H2, supporting industrial uptake and EU climate objectives.

ENDURE project logo

ENDURE PERT diagram

ENDURE innovation

ENDURE consortium