A Fluorination Method for Improving Cation‐Disordered Rocksalt Cathode Performance

A Fluorination Method for Improving Cation‐Disordered Rocksalt Cathode Performance

TitleA Fluorination Method for Improving Cation‐Disordered Rocksalt Cathode Performance
Publication TypeJournal Article
Year of Publication2020
AuthorsJuhyeon Ahn, Dongchang Chen, Guoying Chen
JournalAdvanced Energy Materials
Pagination2001671
Date Published09/2020
ISSN1614-6832
Abstract

In Li‐rich cation‐disordered rocksalt oxide cathodes (DRX), partial fluorine substitution in the oxygen anion sublattice can increase the capacity contribution from transition‐metal (TM) redox while reducing that from the less reversible oxygen redox. To date, limited fluorination substitution has been achieved by introducing LiF precursor during the solid‐state synthesis. To take full advantage of the fluorination effect, however, a higher F content is desired. In the present study, the successful use of a fluorinated polymeric precursor is reported to increase the F solubility in DRX and the incorporation of F content up to 10–12.5 at% into the rocksalt lattice of a model Li‐Mn‐Nb‐O (LMNO) system, largely exceeding the 7.5 at% limit achieved with LiF synthesis. Higher F content in the fluorinated‐DRX (F‐DRX) significantly improves electrochemical performance, with a reversible discharge capacity of ≈255 mAh g−1 achieved at 10 at% of F substitution. After 30 cycles, up to a 40% increase in capacity retention is achieved through the fluorination. The study demonstrates the feasibility of using a new and effective fluorination process to synthesize advanced DRX cathode materials.

DOI10.1002/aenm.202001671
Short TitleAdv. Energy Mater.
Refereed DesignationRefereed