Eliminating hydrogen back-diffusion in electrochemical hydrogen compressors

R&D Focus Areas:
Technology integration process improvement

Lead Organisation:
The University of Melbourne

Funding:
Future Energy Exports CRC (PhD Project)

Status:
Active

Start date:
2022

Completion date:
2025

Project summary description:
To achieve reliable transportation and storage of hydrogen, new compressor technology is required.  Conventional compressors were developed by mechanical engineers, and so are dependent on mechanical parts (that are loud and inefficient) and which essentially push hydrogen to a higher pressure.

An alternative approach is to take advantage of electrochemical means to pressurise hydrogen. This uses an electrical potential to pull hydrogen across an electrode-electrolyte assembly as protons and concentrate (pressurise) hydrogen on the far side. There are no moving parts, enabling the process to be considerably more efficient. However, the concentration of pressured hydrogen at the electrode results in substantial back diffusion of hydrogen through the assembly, in the form of molecular hydrogen.  This is because the electrolytes used, generally the polymer Nafion, have high fractional free volume in which hydrogen can easily permeate.

This project will investigate alternative electrolytes that are more densely constructed to resist hydrogen permeate. However, to prevent a trade-off in loss of proton transfer ability with decreased hydrogen back-diffusion within the electrolyte polymer, it will be necessary to incorporate proton carriers as discrete entities within the denser electrolyte.

These proton carriers will be a range of materials, such as water-soluble nanoparticles, inorganic particles as well as functionalised polymers.  The objective is to utilise the proton carrier ability of these materials to enhance the proton transfer through the denser electrolyte structure and avoid the trade-off in performance.  Furthermore, the presence of the proton carriers will better regulate the humidity level of the electrolyte, a significant problem with current electrochemical compressors.

The outcome of the project will be a robust electrolyte material that can successfully be implemented in hydrogen electrochemical compressors for high pressure outputs.

Further information:
https://www.fenex.org.au/connect/

 

Reviewed: September 2024