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arXiv · 1505.07731

The intercalation phase diagram of Mg in V$_2$O$_5$ from first principles

Gopalakrishnan Sai Gautam·Pieremanuele Canepa·Aziz Abdellahi·Alexander Urban·Rahul Malik·Gerbrand Ceder
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Abstract

We have investigated Mg intercalation into orthorhombic V$_2$O$_5$, one of only three cathodes known to reversibly intercalate Mg ions. By calculating the ground state Mg$_x$V$_2$O$_5$ configurations and by developing a cluster expansion for the configurational disorder in $δ$-V$_2$O$_5$, a full temperature-composition phase diagram is derived. Our calculations indicate an equilibrium phase separating behavior between fully demagnesiated $α$-V$_2$O$_5$ and fully magnesiated $δ$-V$_2$O$_5$, but also motivate the existence of potentially metastable solid solution transformation paths in both phases. We find significantly better mobility for Mg in the $δ$ polymorph suggesting that better performance can be achieved by cycling Mg in the $δ$ phase.

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Gopalakrishnan Sai Gautam, Pieremanuele Canepa, Aziz Abdellahi, Alexander Urban, Rahul Malik, Gerbrand Ceder. 2015-05-28. The intercalation phase diagram of Mg in V$_2$O$_5$ from first principles. https://doi.org/10.1021/acs.chemmater.5b00957

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