Medium Temperature Water Electrolysers (Medlys)

Project summary

Hydrogen has the potential to provide a reliable, secure and clean source of power. Water offers a practical way of hydrogen production in association with renewable energy sources. The main challenges for water electrolysers are high cost, low efficiency and insufficient lifetime.

The strategy of MEDLYS for addressing these issues is to develop novel materials and technologies for a medium temperature steam electrolyser operating at 200-400°C. This temperature range is optimal for;

  1. Improving thermodynamics and kinetics of the process, 
  2. Potentially replacing noble metal based catalysts with cost-effective alternatives,
  3. Allowing for a wide selection of construction materials from metals, ceramics and thermal plastics for conducting, insulating or sealing purposes
  4. Maintaining long-term durability.

MEDLYS will start with development of fundamental materials including an inorganic/composite proton conducting electrolyte, alternative catalysts and other construction materials (electrode substrate, current collector, and bipolar plate). Based on these materials, electrolyser components will be manufactured and a lab-scale cell will be constructed for evaluation and concept-proof testing.

The project is based on the results from ongoing activities within DSF HyCycle Center by most of the consortium partners, who have expertise from materials science and technological know-how coupled with a strong intention to further exploit the achievements of the previous project. The fulfillment of MEDLYS objectives is believed to bring breakthroughs in the hydrogen production technology, which would promote the renewable energy technologies on a national as well as European and global level. 

Total budget for 4 years 16.2 million DKr, funding from the Danish Council for Strategic Research is 13,4 million DKr.

Objective of the project


The overall target is to develop highly efficient water electrolysers for hydrogen generation working at 200 - 400°C based on inorganic or composite proton conductors as electrolytes.

The proposed technology will work in a temperature range between the working range of high temperature PEM cells and solid oxide electrolyser cells. Today, the rather low efficiency of water electrolysis (for alkaline electrolysers about 65%) or the high content of noble elements in the electrocatalyst (PEM electrolysers) are probably the most important hindrances to its wider use for storing renewable energy in the form of hydrogen. A significant cost reduction and improvement in efficiency is required if water electrolysis shall become an economically feasible solution to the future requirements concerning energy supply/demand. The high working temperature favours the kinetics and the thermodynamics, making it possible to find new and cheaper non-noble metal materials showing sufficient catalytic activity at 200-400°C. The challenge is that such materials at the same time must be chemically resistant to the conditions in the electrolyser cell. The corrosion problems are expected to be the most severe at the oxygen evolution electrode, where – in addition to the acidity - a strongly anodic potential is present.


Erik Christensen
Senior researcher
DTU Energy
+45 45 25 23 06
14 JUNE 2024