Fast kinetics of multivalent intercalation chemistry enabled by solvated magnesium-ions into self-established metallic layered materials.

Li, Zhenyou; Mu, Xiaoke; Zhao-Karger, Zhirong; Diemant, Thomas; Behm, R Jürgen; Kübel, Christian; Fichtner, Maximilian · Nat Commun · 2018

basic_science · Level V

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Abstract

Rechargeable magnesium batteries are one of the most promising candidates for next-generation battery technologies. Despite recent significant progress in the development of efficient electrolytes, an on-going challenge for realization of rechargeable magnesium batteries remains to overcome the sluggish kinetics caused by the strong interaction between double charged magnesium-ions and the intercalation host. Herein, we report that a magnesium battery chemistry with fast intercalation kinetics in the layered molybdenum disulfide structures can be enabled by using solvated magnesium-ions ([Mg(DME)<sub>x</sub>]<sup>2+</sup>). Our study demonstrates that the high charge density of magnesium-ion may be mitigated through dimethoxyethane solvation, which avoids the sluggish desolvation process at the cathode-electrolyte interfaces and reduces the trapping force of the cathode lattice to the cations, facilitating magnesium-ion diffusion. The concept of using solvation effect could be a general and effective route to tackle the sluggish intercalation kinetics of magnesium-ions, which can potentially be extended to other host structures.