| Full text | |
| Author(s): |
Total Authors: 3
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| Affiliation: | [1] Univ Sao Paulo, Inst Quim, Dept Quim Fundamental, Ave Prof Lineu Prestes 748, BR-0550800 Sao Paulo, SP - Brazil
Total Affiliations: 1
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| Document type: | Journal article |
| Source: | Electrochimica Acta; v. 372, MAR 10 2021. |
| Web of Science Citations: | 2 |
| Abstract | |
The use of water-in-salt electrolytes (WiSEs) in electrochemical capacitors is an interesting alternative to state-of-the-art electrolytes based on organic solvents. However, making use of their wide electrochemical stability in electrochemical capacitors has been challenging, as shown in battery materials. In this work, we used three concentrations of LiTf2N in water (7, 15 and 21 mol kg(-1)) with activated carbon, and the determination of the maximum operating voltage showed stability up to 2.2, 2.4 and 2.6 V, respectively. This determination suggested positive/negative-electrode mass balances of 2.1, 1.5 and 1.2, but the experiments showed that the cycle life of devices using WiSEs of 15 and 21 mol kg(-1) can be improved. Thus, we find that increasing the amount of active material in the positive electrode gave higher capacitance retention over cycling. With the optimization for a longer cycle life, the observed capacitance retentions for the devices with WiSEs of 7, 15 and 21 mol kg(-1) were 97%, 70% and near 100%, respectively, after 10000 cycles. The higher amount of active material in the positive electrode penalized the energy-power performance, but the higher electrochemical stability compensated for it, and WiSEs of 7, 15 and 21 mol kg(-1) stored 15, 16 and 21 W h kg(-1) when they operated at 0.1 A g(-1). (C) 2021 Elsevier Ltd. All rights reserved. (AU) | |
| FAPESP's process: | 13/22748-7 - Development of High Performance Electrochemical Capacitors Based on Graphene and Ionic Liquids. |
| Grantee: | Vitor Leite Martins |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 18/19459-7 - Ionic liquids mixtures for better supercapacitors |
| Grantee: | Primaggio Silva Mantovi |
| Support Opportunities: | Scholarships in Brazil - Scientific Initiation |
| FAPESP's process: | 15/26308-7 - Optimization of the physicochemical properties of nano -structured materials for applications in molecular recognition, catalysis and energy conversion/storage |
| Grantee: | Roberto Manuel Torresi |
| Support Opportunities: | Research Projects - Thematic Grants |