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Title: Investigation of Key Electronic States in Layered Mixed Chalcogenides With a d 0 Transition Metal as Li‐Ion Cathodes
Abstract Lithium‐rich transition metal chalcogenides are witnessing a revival as candidates for Li‐ion cathode materials, spurred by the boost in their capacities from transcending conventional redox processes based on cationic states and tapping into additional chalcogenide states. A particularly striking case is Li2TiS3‐ySey, which features a d0metal. While the end members are expectedly inactive, substantial capacities are measured when both Se and S are present. Using X‐ray absorption spectroscopy, it is shown that the electronic structure of Li2TiS3‐ySeyis not a simple combination of the end members. The data confirm previous hypotheses that, in Li2TiS2.4Se0.6, this behavior is underpinned by concurrent and reversible redox of only S and Se, and identify key electronic states. Moreover, wavelet transforms of the extended X‐ray absorption fine structure provide direct evidence of the formation of short Se–Se units upon charging. The study uncovers the underpinnings of this intriguing reactivity and highlights the richness of redox chemistry in complex solids.  more » « less
Award ID(s):
2118020
PAR ID:
10540205
Author(s) / Creator(s):
; ; ; ; ; ; ;
Publisher / Repository:
Advanced Functional Materials
Date Published:
Journal Name:
Advanced Functional Materials
ISSN:
1616-301X
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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