Capacity of graphene anode in ionic liquid electrolyte
| Autor: | Agnieszka Swiderska-Mocek, Ewelina Rudnicka, Andrzej Lewandowski, Paweł Jakóbczyk |
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| Jazyk: | angličtina |
| Předmět: |
Materials science
Graphene Inorganic chemistry Exchange current density Electrolyte Electrochemistry Condensed Matter Physics law.invention Dielectric spectroscopy Anode chemistry.chemical_compound chemistry Chemical engineering Materials Science(all) law Ionic liquid General Materials Science Electrical and Electronic Engineering Faraday efficiency |
| Zdroj: | Journal of Solid State Electrochemistry. 18(10):2781-2788 |
| ISSN: | 1432-8488 |
| DOI: | 10.1007/s10008-014-2539-3 |
| Popis: | The graphene anode was investigated in an ionic liquid electrolyte (0.7 M lithium bis(trifluoromethanesulfonyl)imide (LiNTf2)) in room temperature ionic liquid (N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide (MPPyrNTf2)). SEM and TEM images suggested that the electrochemical intercalation/deintercalation process in the ionic liquid electrolyte without vinylene carbonate (VC) leads to small changes on the surface of graphene particles. However, a similar process in the presence of VC results in the formation of a coating (SEI—solid electrolyte interface) on the graphene surface. During charging/discharging tests, the graphene electrode working together with the 0.7 M LiNTf2 in MPPyrNTf2 electrolyte lost its capacity, during cycling and stabilizes at ca. 200 mAh g−1 after 20 cycles. The addition of VC to the electrolyte (0.7 M LiNTf2 in MPPyrNTf2 + 10 wt.% VC) considerably increases the anode capacity. Electrodes were tested at different current regimes: ranging between 50 and 1,000 mA g−1. The capacity of the anode, working at a low current regime of 50 mA g−1, was ca. 1,250 mAh g−1, while the current of 500 mA g−1 resulted in capacity of 350 mAh g−1. Coulombic efficiency was stable and close to 95 % during ca. 250 cycles. The exchange current density, obtained from impedance spectroscopy, was 1.3 × 10−7 A cm−2 (at 298 K). The effect of the anode capacity decrease with increasing current rate was interpreted as the result of kinetic limits of the electrode operation. |
| Databáze: | OpenAIRE |
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