Power capability of LiTDI-based electrolytes for lithium-ion batteries

We report results obtained with lithium 4,5-dicyano-2-(trifluoromethyl) imidazolide (LiTDI), which we believe is a promising lithium salt for electrolytes in lithium-ion batteries. This “Hückel”- type salt has high charge delocalizations which contribute to good lithium-ion dissociation. In addition...

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Bibliographic Details
Published in:Journal of power sources 2015-10, Vol.294, p.507-515
Main Authors: Paillet, Sabrina, Schmidt, Gregory, Ladouceur, Sébastien, Fréchette, Joël, Barray, Francis, Clément, Daniel, Hovington, Pierre, Guerfi, Abdelbast, Vijh, Ashok, Cayrefourcq, Ian, Zaghib, Karim
Format: Article
Language:English
Subjects:
Batteries
Electrolyte
Hückel anion
LiTDI
Lithium ion
Lithium salt
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Summary:We report results obtained with lithium 4,5-dicyano-2-(trifluoromethyl) imidazolide (LiTDI), which we believe is a promising lithium salt for electrolytes in lithium-ion batteries. This “Hückel”- type salt has high charge delocalizations which contribute to good lithium-ion dissociation. In addition, it has high thermal stability and safer degradation products compared to LiPF6, which were identified by TGA-MS. It also does not corrode but passivate the aluminum current collector. Cyclic voltammetry measurements showed a stability up to 4.5 V, which is sufficient for use with standard cathode materials. The power capability of half cells containing LiTDI in EC/DEC was evaluated with standard cathodes used in lithium-ion batteries: LFP, NMC, LCO and LMO. Two LiTDI concentrations were investigated: 1 M and 0.6 M and compared with a reference electrolyte: 1 M LiPF6. In spite of a slightly lower conductivity than the LiPF6, LiTDI (1 M and 0.6 M) shows similar power capability up to 2C with LFP (84% of specific capacity recovered), 10C with NMC (61% of specific capacity recovered), and up to 20C for LMO (88% of specific capacity recovered). Furthermore, better power capability was obtained with 0.6 M LiTDI with LCO, which yielded 82% of specific capacity recovered at 1C (67% for 1 M LiTDI and 1 M LiPF6). [Display omitted] •LiTDI salt showed high thermal stability (285 °C).•Dried and undried LiTDI does not produce HF.•LiTDI salt can be used up to 4.5 V (vs Li+/Li).•Electrolytes containing LiTDI demonstrated power capability similar to that of LiPF6.
ISSN:0378-7753
1873-2755
DOI:10.1016/j.jpowsour.2015.06.073