Realizing continuous cation order-to-disorder tuning in a class of high-energy spinel-type Li-ion cathodes

Date Published
12/2021
Publication Type
Journal Article
Authors
DOI
10.1016/j.matt.2021.10.013
Abstract

Conventional Li-ion cathode materials are dominated by well-ordered structures, in which Li and transition metals occupy distinct crystallographic sites. We show in this paper that profoundly new degrees of freedom for the optimization of electrochemical properties may be accessed if controllable cation disorder is introduced. In a class of high-capacity spinel-type cathode materials, we identify cation to anion ratio in synthesis as a key parameter for tuning the structure continuously from a well-ordered spinel, through a partially ordered spinel, to rocksalt. We find that the varying degree of cation disorder modifies the voltage profile, rate capability, and charge-compensation mechanism in a rational and predictable way. Our results indicate that spinel-type order is most beneficial for achieving high-rate performance as long as the cooperative 8a to 16c phase transition is suppressed, while more rocksalt-like disorder facilitates O redox, which can increase capacity. Our findings reveal an important tuning handle for achieving high energy and power in the vast space of partially ordered cathode materials.

Journal
Matter
Volume
4
Year of Publication
2021
Issue
12
Pagination
3897 - 3916
ISSN Number
25902385
URL
Short Title
Matter
Refereed Designation
Refereed
Organizations
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