Citation: Ouma, C.N.M.; Obodo, K.O.; Bessarabov, D. Computational Approaches to Alkaline Anion-Exchange Membranes for Fuel Cell Applications. Membranes 2022, 12, 1051. https://doi.org/10.3390/ membranes12111051 Academic Editor: Chih-Liang Wang Received: 15 September 2022 Accepted: 21 October 2022 Published: 27 October 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). membranes Review Computational Approaches to Alkaline Anion-Exchange Membranes for Fuel Cell Applications Cecil Naphtaly Moro Ouma, Kingsley Onyebuchi Obodo * and Dmitri Bessarabov * HySA-Infrastructure, Faculty of Engineering, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa * Correspondence: ko.obodo@nwu.ac.za (K.O.O.); dmitri.bessarabov@nwu.ac.za (D.B.) Abstract: Anion-exchange membranes (AEMs) are key components in relatively novel technologies such as alkaline exchange-based membrane fuel cells and AEM-based water electrolyzers. The application of AEMs in these processes is made possible in an alkaline environment, where hydroxide ions (OH - ) play the role of charge carriers in the presence of an electrocatalyst and an AEM acts as an electrical insulator blocking the transport of electrons, thereby preventing circuit break. Thus, a good AEM would allow the selective transport of OH - while preventing fuel (e.g., hydrogen, alcohol) crossover. These issues are the subjects of in-depth studies of AEMs—both experimental and theoretical studies—with particular emphasis on the ionic conductivity, ion exchange capacity, fuel crossover, durability, stability, and cell performance properties of AEMs. In this review article, the computational approaches used to investigate the properties of AEMs are discussed. The different modeling length scales are microscopic, mesoscopic, and macroscopic. The microscopic scale entails the ab initio and quantum mechanical modeling of alkaline AEMs. The mesoscopic scale entails using molecular dynamics simulations and other techniques to assess the alkaline electrolyte diffusion in AEMs, OH - transport and chemical degradation in AEMs, ion exchange capacity of an AEM, as well as morphological microstructures. This review shows that computational approaches can be used to investigate different properties of AEMs and sheds light on how the different computational domains can be deployed to investigate AEM properties. Keywords: alkaline anion-exchange membranes; microscopic; mesoscopic; macroscopic; computational approaches 1. Introduction When it comes to clean and efficient energy technologies for a sustainable future, fuel cells (FCs) are attracting increasing attention. To date, when it comes to research, development, and deployment, it is the low-temperature proton-exchange membrane fuel cells (PEMFC) that dominate, especially within the automotive sector [1,2]. However, alkaline anion-exchange membrane fuel cells (AAEMFCs) have been proposed as a possible challenger to PEMFCs—they have several functional attributes that make them direct competitors to PEMFCs [3]. Compared to PEMFCs, AAEMFCs can create opportunities for cost reduction, mainly due to the switch in operating conditions from an acidic to an alkaline environment/medium [4]. Alkaline media in AAEMFCs create an environment where inexpensive nonprecious metals [4] can be utilized as catalysts, in sharp contrast to PEMFCs which usually utilize expensive precious metals such as platinum-group metals as catalysts due to the acidic operating conditions. In addition, oxygen reduction under alkaline conditions in AAEMFCs is more effective compared to in PEMFCs under acidic conditions. An alkaline medium is also less corrosive and hence creates room for innovation. Figure 1 illustrates the difference between an AAEMFC and a PEMFC. Membranes 2022, 12, 1051. https://doi.org/10.3390/membranes12111051 https://www.mdpi.com/journal/membranes