PhD defence

PhD Defence: Development of Hydrogen Electrodes for Alkaline Water Electrolysis

Thursday 09 Jan 14

Contact

Per Møller
Professor
DTU Mechanical Engineering
+4545 25 48 26

Cecilía K. Kjartansdóttir defends her PhD Friday 17th January at 13:00. The defence takes place in Building 101, room S02. The title of the PhD is "Development of Hydrogen Electrodes for Alkaline Water Electrolysis".

The share of renewable energy worldwide is expected to increase by 38% in the period between 2011 and 2035. Consequently, the share of energy from fluctuating energy sources, such as wind, sun and hydro, will escalate and new alternatives for energy conversion, energy storage and load management will be needed.

Producing hydrogen via water electrolysis using surplus, low cost, power from renewables offers the possibility of increased production capacity and load management with no greenhouse emissions. Hydrogen is a valuable energy carrier, which is able to contribute to various forms of energy, such as, production of electricity via fuel cells, fuel for internal combustion engines or gas turbines, or as a raw material for the production of synthetic fuels via Sabatier or Fischer - Tropsch process. In some situations it may be suitable to simply inject hydrogen into the existing natural gas based infrastructure.

Alkaline water electrolysis (AWE) is the current standard (stat of the art) for industrial largescale water electrolysis systems. One of the main criteria for industrial AWE is efficient and durable electrodes. The aim of the present PhD study was to develop electrode materials for hydrogen production in order to improve the efficiency and durability, and decrease the costs associated with industrial AWE. The primary effort was reserved to the hydrogen electrodes.

Additionally, a new test setup for efficiency and durability measurements was to be designed and constructed. During the present PhD study, new hydrogen electrodes with large electrocatalytic active surface area were developed. The electrodes were produced by physical vapour deposition (PVD) of about 20 μm of aluminium onto a nickel substrate followed by thermo-chemical diffusion and selective aluminium leaching. The obtained electrode surfaces were found to be highly porous; both at micro- and nano-scale, and surface roughness factors of up to 2300 times that of polished nickel were measured.

The electrocatalytic surfaces were characterized to have unique adhesion to the substrate, which is a critical criterion for industrial applications. High Resolution Scanning Electron Microscope (HR-SEM) images reveal highly skeletal structure with pores down to a few nanometres. Half-cell potentiodynamic polarisation curves, recorded at 25C, 200 mA/cm2, show the electrodes to have 385 mV lower hydrogen overpotential and 50 mV lower oxygen overpotential, when compared to polished nickel.

Supervisor: Per Møller.