Engineering of Electrodes and Operating Conditions for Pure-Water-Fed Anion Exchange Membrane Water Electrolyzers

Abstract

Many industrial processes such as petroleum refining, ammonia production, and metal refining have hydrogen gas as a feedstock. Hydrogen gas can be produced via fossil fuel reforming, photo-electrochemical conversion, thermochemical water decomposition, as well as water electrolysis. Among the various water electrolysis technologies, anion exchange membrane water electrolyzers (AEMWEs) possess possible qualities that will allow for them to out-compete incumbent alkaline electrolyzers and proton exchange membrane electrolyzers PEMWEs). AEMWEs have to possibility to combine platinum group metal–free (PGM-free) catalysts, low-cost cell components and operation at high pressure. It is also desirable for AEMWEs to be operated with a pure water feed, high performance and long life – all of which has been elusive thus far. In this presentation, we will demonstrate device engineering pathways to achieve high performance with pure-water-fed AEMWEs. This was accomplished by optimizing the type and amount of electrocatalyst on both anode and cathode alongside the flow conditions and operating temperature. The optimized pure-water-fed AEMWEs have been successfully operated at steady-state at a voltage below 1.90 V at 1.0 Acm-2 at 80 °C. Differences will be highlighted between DI water and electrolyte-fed systems. The importance of pre-treatment to ensure pure DI-water operation will also be discussed. This work emphasizes the importance of engineering electrodes and operating conditions to reach the highest performance of pure-water-fed AEMWEs, which is expected to allow these devices to out-compete existing water electrolysis technologies.