Article

Rational Design of a Stable Fe‐rich Ni‐Fe Layered Double Hydroxide for the Industrially Relevant Dynamic Operation of Alkaline Water Electrolyzers

Muhammad MehdiEnergy Engineering University of Science and Technology 217 Gajeong‐ro, Yuseong‐gu Daejeon 34113 Republic of KoreaByeong‐Seon AnAnalysis Center for Energy Research R&D Strategy Division Korea Institute of Energy Research 152 Gajeong‐ro, Yuseong‐gu Daejeon 34129 Republic of KoreaHaesol KimDepartment of Chemistry Pohang University of Science and Technology Pohang 37673 Republic of KoreaSechan LeeHydrogen Research Department Hydrogen Energy Research Division Korea Institute of Energy Research 152 Gajeong‐ro, Yuseong‐gu Daejeon 34129 Republic of KoreaChangsoo LeeHydrogen Research Department Hydrogen Energy Research Division Korea Institute of Energy Research 152 Gajeong‐ro, Yuseong‐gu Daejeon 34129 Republic of KoreaMyeongmin SeoHydrogen Research Department Hydrogen Energy Research Division Korea Institute of Energy Research 152 Gajeong‐ro, Yuseong‐gu Daejeon 34129 Republic of KoreaMin Wook NohDepartment of Chemistry Pohang University of Science and Technology Pohang 37673 Republic of KoreaWon Chul ChoDepartment of Future Energy Convergence Seoul National University of Science and Technology 232 Gongneung‐ro, Nowon‐gu Seoul 01811 Republic of KoreaChang‐Hee KimSchool of Energy Technology/Hydrogen Energy Korea Institute of Energy Technology 21 KENTECH‐gil Naju 58330 Republic of KoreaChang Hyuck ChoiDepartment of Chemistry Pohang University of Science and Technology Pohang 37673 Republic of KoreaByung‐Hyun KimComputational Science & Engineering Laboratory R&D Strategy Division Korea Institute of Energy Research 152 Gajeong‐ro, Yuseong‐gu Daejeon 34129 Republic of KoreaMinJoong KimEnergy Engineering University of Science and Technology 217 Gajeong‐ro, Yuseong‐gu Daejeon 34113 Republic of KoreaHyun‐Seok ChoEnergy Engineering University of Science and Technology 217 Gajeong‐ro, Yuseong‐gu Daejeon 34113 Republic of Korea

2023en

ABI

Abstract

Abstract Nickel‐iron layered double hydroxides (Ni‐Fe LDHs) consist of stacked Fe 3+ ‐doped positively charged Ni‐hydroxide layers containing charge‐balancing anions and water molecules between the layers. Although Ni‐Fe LDHs are highly active in the oxygen evolution reaction (OER) under alkaline conditions, their poor operational stability remains an issue. Herein, based on density functional theory calculations, it is proposed that the inclusion of a higher Fe content (>40%) than the theoretical Fe 3+ limit (≈25%) permitted by Ni‐Fe LDHs can lead to improved structural stability. An Fe‐rich Ni‐Fe LDH electrode is therefore prepared via a growth strategy based on the controlled oxygen corrosion of an Fe substrate, by enabling the incorporation of additional Fe 2+ into the Ni 2+ ‐Fe 3+ LDH structure. Indeed, microstructural and elemental analysis confirm the presence of additional Fe 2+ . This Fe‐rich Ni‐Fe LDH electrode not only offers a low OER overpotential (≈270 mV at 200 mA cm −2 ) but also exhibits an excellent operational stability under dynamic operating environments without any significant performance degradation or metal ion dissolution. Finally, the practical feasibility of the Fe‐rich Ni‐Fe LDH electrode is demonstrated in a single‐cell (34.56 cm 2 ) operation. These findings are expected to aid in the development of reliable OER electrodes for use in commercial water electrolyzers.

Identifiers

DOI: 10.1002/aenm.202204403

Citations and references

Cited by 20 references

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