Protic ionic liquids as innovative electrolytes for lithium-ion batteries
Acoustics
Solid State and Surface Chemistry, Material Synthesis
Final Report Abstract
The objective of the project "Protic ionic liquids as electrolytes for lithium-ion batteries" was to acquire new insight about the chemical-physical properties of protic ionic liquids (PILs) in view of their use as electrolytes for lithium-ion batteries (LIBs). PILs are a subset of ILs and they are typically synthesized by neutralization reactions of a Brønsted acid (proton donor) and a Brønsted base (proton acceptor). PILs display all favorable properties of ionic liquids, but they have the advantage of being easier to synthesize and cheaper compared to aprotic ionic liquids (AILs). Clearly, these properties make them interesting candidates for use as electrolyte components for electrochemical devices. In the past PILs have been proposed as electrolytes for fuel cells and supercapacitors. It is interesting to notice that for very long time the use of PIL as electrolytes components for LIBs, however, was not considered. The availability of an acidic proton and its strong reactivity towards lithium were seen as an obstacle for the introduction of PILs into these devices, and consequently all efforts were focused on AILs. The project was therefore dedicated to a novel application of these ionic liquids. During the time of the project several PILs have been synthesized and characterized. The result of these studies showed that the viscosities, ionic conductivities and thermal stabilities of PILs are comparable to that of AILs, and they are strongly affected by the characteristic of the cation, e.g. ring size and the alkyl chain length, as well as by the characteristics of the anion. Furthermore, it has been showed that the characteristic of the cation has a strong influence on the ion-ion interactions taking place in these ILs and, in return, also in PIL-based electrolytes suitable for LIBs. The lithium average coordination number in PILs is influenced by (ring) size and the number of protons of the cations and, very important, it might be significantly lower (more than 60%) of that of AILs. PIL-based electrolytes have been utilized in combination with several cathodic and anodic materials suitable for LIB and the results of these studies indicated that the use of PIL-based electrolytes enable the realization of systems with higher performance compared to the classical AIL-based electrolytes, which are able to operate between -20°C and 80°C. Furthermore, also the use of PIL-based electrolytes in sodium-based devices has been investigated. It has been shown, for the first time, that PILs can be also utilized as electrolytes for this emerging electrochemical energy storage devices. Considering these results, PILs can be therefore considered as new and interesting class of electrolytes for LIBs.
Publications
- The Influence of Cation Structure on the Chemical-Physical Properties of Protic Ionic Liquids, The Journal of Physical Chemistry Part C, 120, 8525-8533 (2016)
T. Vogl, P. Goodrich, J. Jacquemin, S. Passerini, A. Balducci
(See online at https://doi.org/10.1021/acs.jpcc.6b01945) - The Use of Protic Ionic Liquids with Cathodes for Sodium-Ion Batteries, Journal of Mat. Chem. A. 4, 10472 – 10478 (2016)
T. Vogl, C. Vaalma, D. Buchholz, M. Secchiaroli, R. Marasis, S. Passerini, A. Balducci
(See online at https://doi.org/10.1039/c6ta02277d) - Ionic liquid in Lithium-Ion Batteries, Topics in Current Chemistry, 2, 375 (2017)
A. Balducci
(See online at https://doi.org/10.1007/s41061-017-0109-8) - Structural Investigations on Lithium-doped Protic and Aprotic Ionic Liquids, Journal of Physical Chemistry B, 121, 5279-5292 (2017)
P. Ray, T. Vogl, A. Balducci, B. Kirchner
(See online at https://doi.org/10.1021/acs.jpcb.7b02636) - The impact of mixtures of protic ionic liquids on the operative temperature range of use of battery systems, Electrochemistry Communications, 78, 47-50 (2017)
T. Vogl, S. Passerini, A. Balducci
(See online at https://doi.org/10.1016/j.elecom.2017.04.002) - Imidazolium-based Protic Ionic Liquids as Electrolytes for Lithium-Ion Batteries, Batteries & Supercaps
T. Stettner, F. C. Walter, A. Balducci
(See online at https://doi.org/10.1002/batt.201800096) - Mixtures of Glyme and aprotic-protic ionic liquids as electrolytes for energy storage devices, Journal of Chemical Physics 148, 193822 (2018)
T. Stettner, P. Huang, M. Goktas, P. Adelhelm, A. Balducci
(See online at https://doi.org/10.1063/1.5013117) - Molecular dynamics simulations of lithium doped ionic-liquid electrolytes, Journal of Physical Chemisty B, 111, 10535-10547 (2018)
P. Ray, A. Balducci, B. Kirchner
(See online at https://doi.org/10.1021/acs.jpcb.8b06022) - Protic and aprotic ionic liquids in combination with hard carbon for lithium-ion and sodium-ion batteries, Batteries & Supercaps, 1, 204-2018 (2018)
M. Arnaiz, P. Huang, J. Ajuria, T. Rojo, E. Goikolea, A. Balducci
(See online at https://doi.org/10.1002/batt.201800073)
