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Direct Observations of the Formation and Redox‐Mediator‐Assisted Decomposition of Li 2 O 2 in a Liquid‐Cell Li–O 2 Microbattery by Scanning Transmission Electron Microscopy
Author(s) -
Yang Chuchu,
Han Jiuhui,
Liu Pan,
Hou Chen,
Huang Gang,
Fujita Takeshi,
Hirata Akihiko,
Chen Mingwei
Publication year - 2017
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201702752
Subject(s) - ostwald ripening , electrolyte , materials science , tetrathiafulvalene , redox , electrode , scanning electron microscope , crystallization , phase (matter) , scanning transmission electron microscopy , transmission electron microscopy , analytical chemistry (journal) , chemical engineering , inorganic chemistry , chemistry , nanotechnology , organic chemistry , molecule , engineering , metallurgy , composite material
Operando scanning transmission electron microscopy observations of cathodic reactions in a liquid‐cell Li–O 2 microbattery in the presence of the redox mediator tetrathiafulvalene (TTF) in 1.0 m LiClO 4 dissolved dimethyl sulfoxide electrolyte are reported. It is found that the TTF addition does not obviously affect the discharge reaction for the formation of a solid Li 2 O 2 phase. The coarsening of Li 2 O 2 nanoparticles occurs via both conventional Ostwald ripening and nonclassical crystallization by particle attachment. During charging, the oxidation reaction at significantly reduced charge potentials mainly takes place at Li 2 O 2 /electrolyte interfaces and has obvious correspondence with the oxidized TTF + distributions in the electric fields of the charged electrode. This study provides direct evidence that TTF truly plays a role in promoting the decomposition of Li 2 O 2 as a soluble charge‐transfer agent between the electrode and the Li 2 O 2 .