Pyrrolidinium Containing Ionic Liquid Electrolytes for Li-Based Batteries

• Main Authors: Louise M. McGrath, James F. Rohan
• Format: Article
• Language: English
• Published: MDPI AG 2020-12-01
• Series: Molecules
• Subjects: anode; cathode; electrolyte; energy storage; ionic liquids; lithium ion batteries
• Online Access: https://www.mdpi.com/1420-3049/25/24/6002

Ionic liquids are potential alternative electrolytes to the more conventional solid-state options under investigation for future energy storage solutions. This review addresses the utilization of IL electrolytes in energy storage devices, particularly pyrrolidinium-based ILs. These ILs offer favorable properties, such as high ionic conductivity and the potential for high power drain, low volatility and wide electrochemical stability windows (ESW). The cation/anion combination utilized significantly influences their physical and electrochemical properties, therefore a thorough discussion of different combinations is outlined. Compatibility with a wide array of cathode and anode materials such as LFP, V₂O₅, Ge and Sn is exhibited, whereby thin-films and nanostructured materials are investigated for micro energy applications. Polymer gel electrolytes suitable for layer-by-layer fabrication are discussed for the various pyrrolidinium cations, and their compatibility with electrode materials assessed. Recent advancements regarding the modification of typical cations such a 1-butyl-1-methylpyrrolidinium, to produce ether-functionalized or symmetrical cations is discussed.