Water-in-salt electrolytes made saltier by Gemini ionic liquids for highly efficient Li-ion batteries

Aleksandar Tot; Leiting Zhang; Erik J Berg; Per H Svensson; Lars Kloo

doi:10.1038/s41598-023-29387-1

Water-in-salt electrolytes made saltier by Gemini ionic liquids for highly efficient Li-ion batteries

Sci Rep. 2023 Feb 7;13(1):2154. doi: 10.1038/s41598-023-29387-1.

Authors

Aleksandar Tot¹, Leiting Zhang², Erik J Berg², Per H Svensson³, Lars Kloo⁴

Affiliations

¹ Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology, SE-10044, Stockholm, Sweden.
² Department of Chemistry - Ångström Laboratory, Uppsala University, SE-751 21, Uppsala, Sweden.
³ Chemical and Pharmaceutical Development, RISE Research Institutes of Sweden, SE-151 36, Södertälje, Sweden.
⁴ Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology, SE-10044, Stockholm, Sweden. larsa@kth.se.

Abstract

The water-in-salt electrolytes have promoted aqueous Li-ion batteries to become one of the most promising candidates to overcome safety concerns/issues of traditional Li-ion batteries. A simple increase of Li-salt concentration in electrolytes can successfully expand the electrochemical stability window of aqueous electrolytes beyond 2 V. However, necessary stability improvements require an increase in complexity of the ternary electrolytes. Here, we have explored the effects of novel, Gemini-type ionic liquids (GILs) as a co-solvent systems in aqueous Li[TFSI] mixtures and investigated the transport properties of the resulting electrolytes, as well as their electrochemical performance. The devices containing pyrrolidinium-based GILs show superior cycling stability and promising specific capacity in the cells based on the commonly used electrode materials LTO (Li₄Ti₅O₁₂) and LMO (LiMn₂O₄).

Abstract

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