Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers

Environmental issues make the quest for better and cleaner energy sources a priority. Worldwide, researchers and companies are continuously working on this matter, taking one of two approaches: either finding new energy sources or improving the efficiency of existing ones. Hydrogen is a well-known e...

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Main Authors: Ana L. Santos, Maria-João Cebola, Diogo M. F. Santos
Format: Article
Language:English
Published: MDPI AG 2021-05-01
Series:Energies
Subjects:
Online Access:https://www.mdpi.com/1996-1073/14/11/3193
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spelling doaj-d521045ed4a4438aa35f44fa0340226d2021-06-01T01:37:46ZengMDPI AGEnergies1996-10732021-05-01143193319310.3390/en14113193Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water ElectrolyzersAna L. Santos0Maria-João Cebola1Diogo M. F. Santos2TecnoVeritas—Serviços de Engenharia e Sistemas Tecnológicos, Lda, 2640-486 Mafra, PortugalCBIOS—Center for Research in Biosciences & Health Technologies, Universidade Lusófona de Humanidades e Tecnologias, Campo Grande 376, 1749-024 Lisbon, PortugalCenter of Physics and Engineering of Advanced Materials (CeFEMA), Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, PortugalEnvironmental issues make the quest for better and cleaner energy sources a priority. Worldwide, researchers and companies are continuously working on this matter, taking one of two approaches: either finding new energy sources or improving the efficiency of existing ones. Hydrogen is a well-known energy carrier due to its high energy content, but a somewhat elusive one for being a gas with low molecular weight. This review examines the current electrolysis processes for obtaining hydrogen, with an emphasis on alkaline water electrolysis. This process is far from being new, but research shows that there is still plenty of room for improvement. The efficiency of an electrolyzer mainly relates to the overpotential and resistances in the cell. This work shows that the path to better electrolyzer efficiency is through the optimization of the cell components and operating conditions. Following a brief introduction to the thermodynamics and kinetics of water electrolysis, the most recent developments on several parameters (e.g., electrocatalysts, electrolyte composition, separator, interelectrode distance) are highlighted.https://www.mdpi.com/1996-1073/14/11/3193alkaline water electrolysiscell componentsefficiencyelectrocatalystsoverpotential
collection DOAJ
language English
format Article
sources DOAJ
author Ana L. Santos
Maria-João Cebola
Diogo M. F. Santos
spellingShingle Ana L. Santos
Maria-João Cebola
Diogo M. F. Santos
Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers
Energies
alkaline water electrolysis
cell components
efficiency
electrocatalysts
overpotential
author_facet Ana L. Santos
Maria-João Cebola
Diogo M. F. Santos
author_sort Ana L. Santos
title Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers
title_short Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers
title_full Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers
title_fullStr Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers
title_full_unstemmed Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers
title_sort towards the hydrogen economy—a review of the parameters that influence the efficiency of alkaline water electrolyzers
publisher MDPI AG
series Energies
issn 1996-1073
publishDate 2021-05-01
description Environmental issues make the quest for better and cleaner energy sources a priority. Worldwide, researchers and companies are continuously working on this matter, taking one of two approaches: either finding new energy sources or improving the efficiency of existing ones. Hydrogen is a well-known energy carrier due to its high energy content, but a somewhat elusive one for being a gas with low molecular weight. This review examines the current electrolysis processes for obtaining hydrogen, with an emphasis on alkaline water electrolysis. This process is far from being new, but research shows that there is still plenty of room for improvement. The efficiency of an electrolyzer mainly relates to the overpotential and resistances in the cell. This work shows that the path to better electrolyzer efficiency is through the optimization of the cell components and operating conditions. Following a brief introduction to the thermodynamics and kinetics of water electrolysis, the most recent developments on several parameters (e.g., electrocatalysts, electrolyte composition, separator, interelectrode distance) are highlighted.
topic alkaline water electrolysis
cell components
efficiency
electrocatalysts
overpotential
url https://www.mdpi.com/1996-1073/14/11/3193
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