Exploiting Cationic Vacancies for Increased Energy Densities in Dual-Ion Batteries

Toshinari Koketsu, Jiwei Ma, Benjamin Morgan, Monique Body, Christophe Legein, Pooja Goddard, Olaf Borkiewicz, Peter Strasser, Damien Dambournet

Research output: Contribution to journalArticle

Abstract

Dual-ion Li–Mg batteries offer a potential route to cells that combine desirable properties of both single-ion species. To maximize the energy density of a dual-ion battery, we propose a strategy for achieving simultaneous intercalation of both ionic species, by chemically modifying the intercalation host material to produce a second, complementary, class of insertion sites. We show that donor-doping of anatase TiO2 to form large numbers of cationic vacancies allows the complementary insertion of Li+ and Mg2+ in a dual-ion cell with a net increase in cell energy density, due to a combination of an increased reversible capacity, an increased operating voltage, and a reduced polarization. By tuning the lithium concentration in the electrolyte, we achieve full utilization of the Ti4+/Ti3+ redox couple with excellent cyclability and rate capability. We conclude that native interstitial sites preferentially accommodate Li+ ions, while Mg2+ ions occupy single-vacancy sites. We also predict a narrow range of electrochemical conditions where adjacent vacancy pairs preferentially accommodate one ion of each species, i.e., a [LiTi+MgTi] configuration. These results demonstrate the implementation of additional host sites such as cationic sites as an effective approach to increase the energy density in dual-ion batteries.
Original languageEnglish
JournalEnergy Storage Materials
Early online date24 Oct 2019
DOIs
Publication statusE-pub ahead of print - 24 Oct 2019

Cite this

Exploiting Cationic Vacancies for Increased Energy Densities in Dual-Ion Batteries. / Koketsu, Toshinari; Ma, Jiwei; Morgan, Benjamin; Body, Monique; Legein, Christophe; Goddard, Pooja; Borkiewicz, Olaf; Strasser, Peter; Dambournet, Damien.

In: Energy Storage Materials, 24.10.2019.

Research output: Contribution to journalArticle

Koketsu, T, Ma, J, Morgan, B, Body, M, Legein, C, Goddard, P, Borkiewicz, O, Strasser, P & Dambournet, D 2019, 'Exploiting Cationic Vacancies for Increased Energy Densities in Dual-Ion Batteries', Energy Storage Materials. https://doi.org/10.1016/j.ensm.2019.10.019
Koketsu, Toshinari ; Ma, Jiwei ; Morgan, Benjamin ; Body, Monique ; Legein, Christophe ; Goddard, Pooja ; Borkiewicz, Olaf ; Strasser, Peter ; Dambournet, Damien. / Exploiting Cationic Vacancies for Increased Energy Densities in Dual-Ion Batteries. In: Energy Storage Materials. 2019.
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AU - Goddard, Pooja

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