Ordered oxygen vacancies in the lithium-rich oxide Li4CuSbO5.5, a triclinic structure type derived from the cubic rocksalt structure

Perez, Arnaud, Vasylenko, Andrij, Surta, TW, Niu, Hongjun, Daniels, Luke ORCID: https://orcid.org/0000-0002-7077-6125, Hardwick, Laurence ORCID: https://orcid.org/0000-0001-8796-685X, Dyer, Matthew ORCID: https://orcid.org/0000-0002-4923-3003, Claridge, John ORCID: https://orcid.org/0000-0003-4849-6714 and Rosseinsky, Matthew ORCID: https://orcid.org/0000-0002-1910-2483 (2021) Ordered oxygen vacancies in the lithium-rich oxide Li4CuSbO5.5, a triclinic structure type derived from the cubic rocksalt structure. [Data Collection]

Data Catalogue DOI: 10.17638/datacat.liverpool.ac.uk/1540

Description

Li-rich rocksalt oxides are promising candidates as high energy density cathode materials for next generation Li-ion batteries because they present extremely diverse structures and compositions. Most reported materials in this family contain as many cations as anions, a characteristic of the ideal cubic closed-packed rocksalt composition. In this work, a new rocksalt-derived structure type is stabilized by selecting divalent Cu and pentavalent Sb cations to favor the formation of oxygen vacancies during synthesis. The structure and composition of the oxygen deficient Li4CuSbO5.5□0.5 phase is characterized by combining X-ray and neutron diffraction, ICP-OES, XAS and magnetometry measurements. The ordering of cations and oxygen vacancies is discussed in comparison with the related Li2CuO2□1 and Li5SbO5□1 phases. The electrochemical properties of this material are presented, with only 0.55 Li+ extracted upon oxidation corresponding to a limited utilization of cationic and/or anionic redox, whereas more than 2 Li+ ions can be reversibly inserted upon reduction to 1 V vs Li+/Li, a large capacity attributed to a conversion reaction and the reduction of Cu2+ to Cu0. Control of the formation of oxygen vacancies in Li-rich rocksalt oxides by selecting appropriate cations and synthesis conditions affords a new route for tuning the electrochemical properties of cathode materials for Li-ion batteries. Furthermore, the development of material models of the required level of detail to predict phase diagrams and electrochemical properties, including oxygen release in Li-rich rocksalt oxides, still rely on the accurate prediction of crystal structures. Experimental identification of new accessible structure types stabilized by oxygen vacancies represents a valuable step forward in the development of predictive models.

Keywords:

Lithium-ion battery, cathode material, Li-rich rocksalt oxide, oxygen vacancy

Divisions:

Faculty of Science and Engineering > School of Physical Sciences > Chemistry

Depositing User:

Luke Daniels

Date Deposited:

16 Feb 2023 16:40

Last Modified:

16 Feb 2023 17:30

DOI:

10.17638/datacat.liverpool.ac.uk/1540