Ionic liquid electrolyte additive regulates the multi-species-insertion titanium sulfide cathode for magnesium batteries

Morag A, Chu X, Neumann C, Pohl D, Borrelli M, Sabaghi D, Loeffler M, Sofer Z, Turchanin A, Yu M, Feng X (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Energy Storage Materials Elsevier

Book Volume: 53

Pages Range: 435-443

DOI: 10.1016/j.ensm.2022.09.021

Abstract

Benefiting from the appealing Mg metal anodes, magnesium batteries (MBs) present attractive potential as sustainable batteries of tomorrow. However, the Mg metal anode-compatible electrolytes generally contain large-size and strongly bonded Mg-clusters (i.e., MgxCly^2x-y), resulting in the inefficient cathode chemistries associated with the sluggish Mg-species insertion. Here, using the iconic TiS2 cathode, we demonstrate the pronounced effect of ionic liquid on regulating MgxCly^2x-y clusters in the MB electrolyte and promoting the high-kinetics multi-Mg-species insertion into TiS2. Specifically, the addition of 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide (PP14TFSI) ionic liquid into the conventional Mg bis(hexamethyldisilazide)/4MgCl2 electrolyte induces a nontrivial two-plateau charge/discharge profile of the TiS2 electrode, in which Mg²⁺ insertion is mainly disclosed at the high-potential plateau and MgCl⁺ insertion dominates the low-potential plateau. Molecular dynamic simulations indicate that the PP14TFSI additive can dissociate large MgxCly^2x-y clusters to produce MgCl⁺, which can be effectively stabilized by PP14⁺ and TFSI^–. Meanwhile, PP14TFSI catalyzes the Mg-Cl dissociation, thus creating the desirable Mg²⁺ species. These electrolyte-regulation effects consequently enable the TiS2 cathode with a decent specific capacity (81 mAh g^–1 at 10 mA g^–1), high rate capability (63 mAh g^–1 at 200 mA g^–1), and long-term durability (86% capacity retention after 500 cycles).

Involved external institutions

Technische Universität Dresden

Germany (DE) Friedrich-Schiller-Universität Jena

Germany (DE) University of Chemistry and Technology (UCT) / Vysoká škola chemicko-technologická (VŠCHT)

Czech Republic (CZ)

How to cite

APA:

Morag, A., Chu, X., Neumann, C., Pohl, D., Borrelli, M., Sabaghi, D.,... Feng, X. (2022). Ionic liquid electrolyte additive regulates the multi-species-insertion titanium sulfide cathode for magnesium batteries. Energy Storage Materials, 53, 435-443. https://doi.org/10.1016/j.ensm.2022.09.021

MLA:

Morag, Ahiud, et al. "Ionic liquid electrolyte additive regulates the multi-species-insertion titanium sulfide cathode for magnesium batteries." Energy Storage Materials 53 (2022): 435-443.

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