Ionic
Liquid-Based Electrolytes for Sodium-Ion Batteries: Tuning Properties
To Enhance the Electrochemical
Performance of Manganese-Based Layered Oxide Cathode
posted on 2019-05-30, 00:00authored byLuciana Gomes Chagas, Sangsik Jeong, Ivana Hasa, Stefano Passerini
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-Na0.6Ni0.22Al0.11Mn0.66O2 cathode
to deliver about 140 mAh g–1 for more than 200 cycles.