Ionic liquids have appealing properties as electrolytes due to their wide electrochemical windows, lack of flammability, moderate conductivities, and structure-property tunability. Due to these characteristics, ionic liquids have been considered for electrolytes in lithium metal and lithium ion batteries. Challenges still exist that limit the application of ionic liquids in lithium-based batteries including poor lithium ion transport, lack of stable solid electrolyte interphase (SEI), and high melting points.
Elizabeth J. Biddinger,
The City College of New York
To address these challenges, co-solvents and additives can be mixed with the ionic liquid to further tune the properties of the electrolyte. We have investigated two families of ionic liquid mixtures as lithium-containing electrolytes: ionic liquid – ester co-solvent mixtures, and ionic liquid – glyme mixtures. In both cases, pyrrolidium-based cations and bis(trifluoromethanesulfonyl)imide ([TFSI]-) anions were utilized for the ionic liquids and LiTFSI served as the base case lithium salt.
The physical and electrochemical characteristics of the ionic liquid mixtures were evaluated to better understand how key properties and solvating power affect reversible lithium deposition and stripping across a range of temperatures. Through the use of ionic liquid-based mixtures, many of the desirable properties of the ionic liquids can be retained while the undesired properties of the ionic liquids can be mitigated, making for more favorable electrolytes.
Elizabeth J. Biddinger is an associate professor of chemical engineering at The City College of New York, the Deputy Director of the Center for Decarbonizing Chemical Manufacturing Using Sustainable Electrification (DC-MUSE) and an associate editor for ACS Sustainable Chemistry & Engineering.
Her research interests are in electrochemical reaction engineering for green chemistry and energy. In particular, she is interested in the electrification of chemical processes that transform wastes or renewable resources into valuable materials, chemicals and fuels for decarbonization and sustainability, and in alternative electrolytes for battery safety and performance.
Professor Biddinger has been recognized with the 2022 Ohio State College of Engineering Texnikoi Alumni Award, 2018 US Department of Energy Early Career Award, 2016-2017 Electrochemical Society – Toyota Young Investigator Fellowship, and 2014 CUNY Junior Faculty Research Award in Science and Engineering (J-FRASE) sponsored by the Sloan Foundation.
Professor Biddinger has held several leadership roles with professional organizations including The Electrochemical Society (ECS) Industrial Electrochemistry & Electrochemical Engineering (IE&EE) Division Vice Chair, Secretary/Treasurer and Student & Early Career Awards Chair, and an American Institute of Chemical Engineers (AIChE) Catalysis and Reaction Engineering Division Director. Prior to joining City College in August 2012, Prof. Biddinger was a post-doctoral fellow at the Georgia Institute of Technology. She received her Ph.D. in 2010 in chemical engineering from The Ohio State University (Columbus, OH) and her BS in 2005 in chemical engineering from Ohio University (Athens, OH).