用于高温应用中高压超级电容器的离子液体电解质选择
Ionic liquid electrolyte selection for high voltage supercapacitors in high-temperature applications.
作者信息
Bahaa Ahmed, Alhammadi Ayoob, Lethesh Kallidanthiyil Chellappan, Susantyoko Rahmat Agung, Bamgbopa Musbaudeen O
机构信息
R&D Centre, Dubai Electricity and Water Authority (DEWA), Dubai, United Arab Emirates.
出版信息
Front Chem. 2024 Mar 4;12:1349864. doi: 10.3389/fchem.2024.1349864. eCollection 2024.
Systematic analyses of electrolyte physicochemical properties are important to screen ionic liquids (ILs) and understand the electrochemical performance of supercapacitor electrolytes. This study harmonizes the evaluation of electrochemical performance and transport properties of eight shortlisted ILs from 22 commercially available hydrophobic ILs toward achieving a 5 V supercapacitor capable of high-temperature operation (up to 353.15 K). The eight ILs are N-Propyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([Pyr ] [TFSI], N-Pentyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([Pyr ] [TFSI]), N-Propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ([Pyr ] [FSI]), 1-Methyl-1-(2-methoxyethyl)pyrrolidinium Bis(trifluoromethanesulfonyl)imide ([Pyr ] [TFSI]), 1-Methyl-1-propylpiperidinium bis(trifluoromethanesulfonyl)imide ([Pip ] [TFSI]), 1-Methyl-1-propylpiperidinium bis(fluorosulfonyl)imide ([Pip ] [FSI]), N-Trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide ([N ] [TFSI]), N-Trimethyl-N-hexylammonium bis(trifluoromethanesulfonyl)imide ([N ] [TFSI]). The density, viscosity, and ionic conductivity of the eight ILs were measured between 278.15 and 373.15 K to confirm the effects of temperature and ion structure before electrochemical characterization. The [FSI]-based ILs ([Pip ] [FSI] and [Pyr ] [FSI]) showed lower densities and viscosities compared to other ILs among the eight based on [TFSI]. Consequently, the highest conductivity was obtained for [Pyr ] [FSI]. Cyclic voltammetry and impedance spectroscopy was performed on supercapacitors assembled with the eight ILs as electrolytes between 298.15-353.15 K. Conclusion from the two-electrode supercapacitors using multi-walled carbon nanotubes showed the 6 most-applicable ILs towards the targeted ≥ 5 V SC at high temperature are [Pip ] [TFSI] (5.4 V), [Pip ] [FSI] (5 V), [N ] [TFSI] (5.1 V), [N ] [TFSI] (5.2 V), [Pyr ] [TFSI] (5.2 V), and [Pyr ] [TFSI] (5.2 V).
对电解质物理化学性质进行系统分析对于筛选离子液体（ILs）和理解超级电容器电解质的电化学性能至关重要。本研究对22种市售疏水性离子液体中入围的8种离子液体的电化学性能和传输性质进行了综合评估，以实现能够在高温（高达353.15 K）下运行的5 V超级电容器。这8种离子液体分别是N-丙基-N-甲基吡咯烷鎓双（三氟甲磺酰）亚胺（[Pyr₁₃][TFSI]）、N-戊基-N-甲基吡咯烷鎓双（三氟甲磺酰）亚胺（[Pyr₁₅][TFSI]）、N-丙基-N-甲基吡咯烷鎓双（氟磺酰）亚胺（[Pyr₁₃][FSI]）、1-甲基-1-（2-甲氧基乙基）吡咯烷鎓双（三氟甲磺酰）亚胺（[Pyr₁₄][TFSI]）、1-甲基-1-丙基哌啶鎓双（三氟甲磺酰）亚胺（[Pip₁₃][TFSI]）、1-甲基-1-丙基哌啶鎓双（氟磺酰）亚胺（[Pip₁₃][FSI]）、N-三甲基-N-丙基铵双（三氟甲磺酰）亚胺（[N₁₃][TFSI]）、N-三甲基-N-己基铵双（三氟甲磺酰）亚胺（[N₁₆][TFSI]）。在进行电化学表征之前，测量了这8种离子液体在278.15至373.15 K之间的密度、粘度和离子电导率，以确认温度和离子结构的影响。与基于[TFSI]的其他8种离子液体相比，基于[FSI]的离子液体（[Pip₁₃][FSI]和[Pyr₁₃][FSI]）密度和粘度较低。因此，[Pyr₁₃][FSI]的电导率最高。在298.15 - 353.15 K之间，以这8种离子液体为电解质组装超级电容器，进行了循环伏安法和阻抗谱分析。使用多壁碳纳米管的两电极超级电容器的结论表明，在高温下最适用于目标≥5 V超级电容器的6种离子液体是[Pip₁₃][TFSI]（5.4 V）、[Pip₁₃][FSI]（5 V）、[N₁₃][TFSI]（5.1 V）、[N₁₆][TFSI]（5.2 V）、[Pyr₁₃][TFSI]（5.2 V）和[Pyr₁₅][TFSI]（5.2 V）。
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