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Interphase Evolution at Two Promising Electrode Materials for Li‐Ion Batteries: LiFePO 4 and LiNi 1/2 Mn 1/2 O 2
Author(s) -
Dupré Nicolas,
Cuisinier Marine,
Martin JeanFrederic,
Guyomard Dominique
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201400070
Subject(s) - x ray photoelectron spectroscopy , interphase , electrochemistry , electrolyte , materials science , electrode , magic angle spinning , chemical engineering , analytical chemistry (journal) , chemistry , nuclear magnetic resonance spectroscopy , organic chemistry , genetics , engineering , biology
The present review reports the characterization and control of interfacial processes occurring on olivine LiFePO 4 and layered LiNi 1/2 Mn 1/2 O 2 , standing here as model compounds, during storage and electrochemical cycling. The formation and evolution of the interphase created by decomposition of the electrolyte is investigated by using spectroscopic tools such as magic‐angle‐spinning nuclear magnetic resonance ( 7 Li, 19 F and 31 P) and electron energy loss spectroscopy, in parallel to X‐ray photoelectron spectroscopy, to quantitatively describe the interphase and unravel its architecture. The influence of the pristine surface chemistry of the active material is carefully examined. The importance of the chemical history of the surface of the electrode material before any electrochemical cycling and the strong correlation between interface phenomena, the formation/evolution of an interphase, and the electrochemical behavior appear clearly from the use of these combined characterization probes. This approach allows identifying interface aging and failure mechanisms. Different types of surface modifications are then investigated, such as intrinsic modifications upon aging in air or methods based on the use of additives in the electrolyte or carbon coatings on the surface of the active materials. In each case, the species detected on the surface of the materials during storage and cycling are correlated with the electrochemical performance of the modified positive electrodes.