The development of alternatives to lithium-ion batteries (LiB) with higher performances while remaining sustainable is one of the key challenges to ensure that a global energy transition is possible. The manipulation of the atomic structure of electrode materials is a unique approach enabling the development of multivalent-ion (MV) batteries, which could replace LiB. Multivalent-ion batteries, which rely on Earth-crust abundant elements such as Mg, can provide high energy density due to multi-electron processes and enhanced safety.<br/>Currently, the realization of these devices has been limited by designing suitable electrode materials. As most of the available electrode materials for LiB fail to accommodate MV, in this study, we propose an innovative approach to allow for the reversible intercalation processes to occur, namely via deliberately introducing defects such as cationic vacancies at the level of the atomic structure of the oxide. These defects favor ion diffusion and can serve as host sites for MV, thereby unlocking the electrochemical activity toward MV. Previously, we showed in anatase, substituting oxide anions with mono-charged (F,OH) anions allows the formation of cationic vacancies. Herein, we show that intercalation capacity is controlled by the vacancy concentration. Our results highlight the potential benefits of chemically controlling cationic defects in oxide materials for rechargeable Mg-ion batteries.

Controlled titanium vacancies in titanium oxide for rechargeable magnesium batteries

2019 Spring National Meeting

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