Water electrolysers produce oxygen and hydrogen, which could be used to store energy from intermittent sources in chemical bonds. However, proton exchange membrane (PEM) electrolysers require expensive materials (e.g. Pt catalyst and Ti porous transport layers) their high capital costs inhibiting their more widespread industrial deployment.
This research aims to address this problem by investigating and improving the performance of an anion exchange membrane (AEM) electrolyser through utilisation of cheaper materials e.g. nickel-based electrodes, and judicious micro-structuring of the latter. Inkjet 3D printing and electrodeposition methods were, for the first time, chosen for electrodes fabrication. In-situ investigation of the kinetics will be performed to comprehend the effect of two-phase flow, electrode catalyst and materials with the goal to decrease the capital costs and bring the its performance to match that of PEM electrolysers. Lower cost will enable countries such as Thailand to adopt the technology easier.
Nickel was chosen as a catalyst for its high conductivity and chemical stability. The process of inkjet 3D printing requires customizable ink to be made for printing of 3D microstructures, e.g. gradient or pillar structures while electrodeposition allows nickel to be deposited on an inexpensive porous material such as carbon cloth. Nickel will provide protection for carbon materials during operation.
Initial nickel electrode fabrication via electrodeposition was successfully done and tested within the AEM electrolyser, exhibiting current density of 78 mA cm-2 at 1.81 V. Preliminary printing of simple 3D structures also demonstrated that NiO ink deposits maintained their mechanical integrity, more complex structures will be further studied.
The kinetics of AEM electrolysers will be investigated by introducing an array of reference electrode probes into the reactor to measure single-side overpotential and resistor probes at different location to measure and map current density gradient.