Journal
CHEMISTRY OF MATERIALS
Volume 29, Issue 22, Pages 9714-9724Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acs.chemmater.7b03434
Keywords
-
Funding
- French National Research Agency (ANR) [ANR-10-EQPX-45]
- European Research Council (ERC) (FP)/ERC [670116-ARPEMA]
Ask authors/readers for more resources
The demonstration of reversible anionic redox in Li-rich layered oxides has revitalized the search for higher energy battery cathodes. To advance the fundamentals of this promising mechanism, we investigate herein the cationic-anionic redox processes in Li2Ru0.23Sn0.23O3-a model Li-rich layered cathode in which Ru (cationic) and O (anionic) are the only redox-active sites. We reveal its charge compensation mechanism and local structural evolutions by applying operando (and complementary ex situ) X-ray absorption spectroscopy (XAS). Among other local effects, the anionic-oxidation-driven distortion of the oxygen network around Ru atoms is thereby visualized. Oxidation of lattice oxygen is also directly proven via hard X-ray photoelectron spectroscopy (HAXPES). Furthermore, we demonstrate a spectroscopy-driven visualization of electrochemical reaction paths, which enabled us to neatly decouple the individual cationic-anionic dQ/dV contributions during cycling. We hence establish the redox and structural origins of all dQ/dV features and demonstrate the vital role of anionic redox in hysteresis and kinetics. These fundamental insights about Li-rich systems are crucial for improving the existing anionic-redox-based cathodes and evaluating the ones being discovered rapidly.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available