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Influence of Additives on the Reversible Oxygen Reduction Reaction/Oxygen Evolution Reaction in the Mg 2+ ‐Containing Ionic Liquid N ‐Butyl‐ N ‐Methylpyrrolidinium Bis(Trifluoromethanesulfonyl)imide
Author(s) -
Eckardt M.,
Alwast D.,
Schnaidt J.,
Behm R. J.
Publication year - 2020
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.202000672
Subject(s) - chemistry , ionic liquid , inorganic chemistry , electrochemistry , passivation , oxygen evolution , oxygen , electrode , catalysis , organic chemistry , layer (electronics)
The influence of different additives on the oxygen reduction reaction/oxygen evolution reaction (ORR/OER) in magnesium‐containing N ‐butyl‐ N ‐methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([BMP][TFSI]) on a glassy carbon electrode was investigated to gain a better understanding of the electrochemical processes in Mg–air batteries. 18‐Crown‐6 was used as a complexing agent for Mg ions to hinder the passivation caused by their reaction with ORR products such as superoxide and peroxide anions. Furthermore, borane dimethylamine complex (NBH) was used as a potential water‐removing agent to inhibit electrode passivation by reacting with trace impurities of water. The electrochemical processes were characterized by differential electrochemical mass spectrometry to monitor the consumed and evolved O 2 in the ORR/OER and determine the number of transferred electrons. Crown ether and NBH efficiently masked Mg 2+ . A stochiometric excess of crown ether resulted in reduced formation of a passivation layer, whereas at too high concentrations the reversibility of the ORR/OER was diminished.