The feasibility of a pyrrolidinium-based room-temperature ionic liquid (RTIL) as the solvent for lithium-ion batteries is tested by analyzing its intercalation behavior and thermal stability. The RTIL-cations are intercalated into a graphitic carbon and a part of them are irreversibly trapped inside the graphene layers. These trapped cations block Li+ intercalation to give only a marginal capacity. In contrast, such a cation insertion/trapping is absent in two non-graphitic carbons; hard carbon and soft carbon. A stable cycle performance with a Li+ insertion capacity of about 200 mAh g - 1 is attained. The absence of RTIL-cation insertion is evidenced by the cyclic voltammograms and Raman spectra. A calorimetric study reveals that this RTIL has a higher thermal stability and less reactivity with lithiated carbons as compared with the carbonate-based solvent. The use of this RTIL solvent for the non-graphitic carbons seems to be feasible.
Bibliographical noteFunding Information:
This work was supported by the WCU program through the National Research Foundation of Korea funded by the MEST ( R31-10013 and NRF-2010-C1AAA001-2010-0029065 ).
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