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Isotopic Labeling Reveals Active Reaction Interfaces for Electrochemical Oxidation of Lithium Peroxide
Author(s) -
Wang Yu,
Lu YiChun
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201901350
Subject(s) - electrochemistry , oxidizing agent , electrolyte , lithium (medication) , chemistry , catalysis , electrode , peroxide , secondary ion mass spectrometry , inorganic chemistry , chemical engineering , analytical chemistry (journal) , mass spectrometry , organic chemistry , medicine , chromatography , engineering , endocrinology
The unresolved debate on the active reaction interface of electrochemical oxidation of lithium peroxide (Li 2 O 2 ) prevents rational electrode and catalyst design for lithium‐oxygen (Li‐O 2 ) batteries. The reaction interface is studied by using isotope‐labeling techniques combined with time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and on‐line electrochemical mass spectroscopy (OEMS) under practical cell operation conditions. Isotopically labelled microsized Li 2 O 2 particles with an Li 2 16 O 2 /electrode interface and an Li 2 18 O 2 /electrolyte interface were fabricated. Upon oxidation, 18 O 2 was evolved for the first quarter of the charge capacity followed by 16 O 2 . These observations unambiguously demonstrate that oxygen loss starts from the Li 2 O 2 /electrolyte interface instead of the Li 2 O 2 /electrode interface. The Li 2 O 2 particles are in continuous contact with the catalyst/electrode, explaining why the solid catalyst is effective in oxidizing solid Li 2 O 2 without losing contact.