Ionic Liquid-Based Electrolytes for Sodium-Ion Batteries: Tuning Properties To Enhance the Electrochemical Performance of Manganese-Based Layered Oxide Cathode

Luciana Gomes Chagas; Sangsik Jeong; Ivana Hasa; Stefano Passerini

doi:10.1021/acsami.9b03813

Ionic Liquid-Based Electrolytes for Sodium-Ion Batteries: Tuning Properties To Enhance the Electrochemical Performance of Manganese-Based Layered Oxide Cathode

ACS Appl Mater Interfaces. 2019 Jun 26;11(25):22278-22289. doi: 10.1021/acsami.9b03813. Epub 2019 Jun 12.

Authors

Luciana Gomes Chagas^{1

2}, Sangsik Jeong^{1

2}, Ivana Hasa^{1

2}, Stefano Passerini^{1

2}

Affiliations

¹ Helmholtz Institute Ulm (HIU) , Helmholtzstrasse 11 , 89081 Ulm , Germany.
² Karlsruhe Institute of Technology (KIT) , P.O. Box 3640, 76021 Karlsruhe , Germany.

PMID: 31144802
DOI: 10.1021/acsami.9b03813

Abstract

Ionic liquids (ILs) are considered as appealing alternative electrolytes for application in rechargeable batteries, including next-generation sodium-ion batteries, because of their safe and eco-friendly nature, resulting from their extremely low volatility. In this work, two groups of advanced pyrrolidinium-based IL electrolytes are concerned, made by mixing sodium bis(fluorosulfonyl)imide (NaFSI) or sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) salts salts with N-methyl- N-propylpyrrolidinium bis(fluorosulfonyl)imide (Pyr₁₃FSI), N-butyl- N-methylpyrrolidinium bis(fluorosulfonyl)imide (Pyr₁₄FSI), and N-butyl- N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr₁₃FSI). The characterization of eight different electrolytes, including single anion electrolytes and binary anion mixtures, in terms of thermal properties, density, viscosity, and conductivity, as well as electrochemical stability window and cycling performance in room-temperature sodium cells, is reported here. Among all of the blends, those containing Pyr₁₄FSI outperform the others in terms of cell performance enabling the layered P2-Na_0.6Ni_0.22Al_0.11Mn_0.66O₂ cathode to deliver about 140 mAh g^-1 for more than 200 cycles.

Keywords: NaFSI; NaTFSI; P2-layered oxide cathode; ionic liquid electrolyte; sodium-ion battery.