Using Impedance to Quantify Transport Losses in Alkaline Water Electrolysis Electrode Catalyst Layers

Abstract

Anthropogenic climate change has brought on a global climate crisis and emergency. Increased levels of atmospheric carbon dioxide levels has brought with it undesirable changes to the world’s climate. To halt and eventually stop this trend the world needs to move to zero-carbon sources of electricity, transport and chemical production. To offset the variability in zero-carbon electricity sources storage or usage of the excess energy is necessary. One of several technologies to achieve this is water electrolysis. A promising candidate of this field of study is Alkaline Water Electrolysis The field of alkaline electrolysis have recently moved from a gap-based macro-material approach to a nanomaterials based membrane cell architecture. Due to recent advances in membrane technology both ion-conduction and electrolyte solvating membranes allow for a zero-gap architecture. With this approach comes new engineering challenges. Bubble formation, -diffusion, -suppresion, and –transport are all phenomena that are recently unexplored in the context of nanopowder-based electrode in flooded KOH systems. One of the ways of exploring this is the use of Galvanostactic Electrochemical Impedance Spectroscopy (GEIS).. Through GEIS investigations and Distribution of Relaxation Times of the electrochemical response of nano-powder based cathodes a Gerischer-like response indicating transport issues and a way of quantifying this.