[NanoIC topic] 2D nanocrystals as water-tight ionic membranes for low-temperature CO2 electrolysis

Electrochemical CO₂ reduction is an attractive option in the field of sustainable energy system, as it turns waste into useful chemical fuels, thus closing the carbon cycle and moving towards a carbon-neutral economy. Electrolyzers are a key technology for electrochemical CO₂ conversion, but several of their components still require significant improvement to achieve higher efficiency and durability. One critical element is the membrane, whose performance is strongly governed by its ion permeability and conductivity.

The major drawback with CO₂ electrolyzers is the low solubility of CO₂ in aqueous electrolytes. Moving from the liquid phase to the purely vapour phase CO₂ electrolysis is an advantageous move. However, the cell lifetime is still limited by excess water transport and flooding of the gas diffusion electrode. In addition, there are other factors such as the transport of cations and carbonate leading to undesired precipitation which further reduce lifetime and productivity. Therefore, a purely vapour phase electrolyser requires certain improvements, including controlled water and ion transport through the membrane.

By implementing fundamental research on nanomaterials, combined with engineering principles, the properties of membranes can be systematically improved. One promising approach is the introduction of a thin-film barrier layer in the electrolyzer, based on inorganic 2D nanocrystals. This can offer a controlled water transport through the membrane, which behave as a solid electrolyte, offering high protonic conductivity and ultimately lowering the cell voltage. This can also act as a selective layer for specific ion transport, which reduces cell voltage further. This makes a meaningful improvement towards the long-term stability of the cell. Henceforth, the implementation of such thin-film barrier layer, in electrochemical devices such as fuel cell or electrolyzers is a promising and advantageous step. 

Work description: The student will perform systematic screening of 2D nanomaterials integrated in the electrolyte/membrane/electrode assembly and tested in the electrolyzer system at imec. Techniques such as wet chemistry and solid-state synthesis will be used for the preparation of 2D nanocrystals. The deposited layer will be characterized by ellipsometry, PXRD, SEM, XPS, and Raman spectroscopy. The conductivity of the layer will be assessed using impedance measurements. Water/electrolyte permeability of the deposited layer will be measured in an external cell under varying gas pressure. The ion’s transport will be quantified by ICP-MS and gas chromatograph, respectively. Initial experiments will be conducted on planar electrodes, and then the optimized system will be implemented on advanced nanomesh electrodes developed at imec.

Contacts: philippe.vereecken@imec.be

                 debittree.choudhury@imec.be

                 matias.jobbagy@imec.be