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Ligand Valency Effects on the Alkaline Stability of Metallopolymer Anion‐Exchange Membranes
Author(s) -
Aggarwal Kanika,
Bsoul Saja,
Li Songlin,
Dekel Dario R.,
Diesendruck Charles E.
Publication year - 2021
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.202100238
Subject(s) - valency , ligand (biochemistry) , cationic polymerization , membrane , nickel , denticity , chemistry , chemical stability , ion exchange , combinatorial chemistry , alkaline fuel cell , polymer chemistry , ion , materials science , inorganic chemistry , organic chemistry , metal , philosophy , biochemistry , linguistics , receptor
Long‐term stability is a key requirement for anion‐exchange membranes (AEMs) for alkaline fuel cells and electrolyzers that is yet to be fulfilled. Different cationic chemistries are being exploited to reach such a goal, and metallopolymers present the unique advantage of chemical stability towards strong nucleophiles as compared to organic cations. Yet, the few metallopolymers tested in strongly alkaline conditions or even in fuel cells still degrade. Therefore, fundamental studies can be advantageous in directing future developments towards this goal. Here, a systematic study of the effect of ligand valency is presented, using nickel‐based metallopolymers on polynorbornene backbones, functionalized with multidentate pyridine ligands. Metallopolymers using a single ligand type as well as all the possible mixtures are prepared and their relative stability towards aggressive alkaline conditions compared. Metallopolymer in which nickel ions are hexacoordinated with two tridentate ligands demonstrates superior stability. More importantly, by comparing all the metallopolymers’ stability, the reason behind such relative stability provides design parameters for novel metallopolymer AEMs.