Phosphonium-containing electrolytes offer a new avenue for advancing high-performance supercapacitors. In this study, for the first time, we investigated the physical and electrochemical characteristics of a new phosphonium salt—tetraethylphosphonium tetrafluoroborate (TEPBF) in various solvents including acetonitrile (AN), propionitrile (PN), propylene carbonate (PC), and trimethyl phosphate (TMP). Our investigations revealed that TEPBF/AN electrolytes demonstrated high solubility (2.15 M), high ionic conductivity (52.2 mS cm), and wide electrochemical stability windows (4.7 V), suggesting that TEPBF/AN emerges as a compelling alternative to conventional ammonium salts in AN for developing high-power and high-voltage supercapacitors. Our results also showed that supercapacitors based on 1 M TEPBF/AN achieved the highest capacitance (24.7 F g), superior rate performance, highest energy (24.9 Wh kg) and power densities (6752 W kg) among the investigated electrolytes. Furthermore, it retained 75 % of its capacitance after 1000 h float test at a high working voltage of 3.2 V, which significantly outperformed other supercapacitors using conventional ammonium salts in AN.

中文翻译：

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四乙基鏻四氟硼酸盐电解质为构建高功率、高电压超级电容器铺平道路


含磷电解质为推进高性能超级电容器提供了新途径。在这项研究中，我们首次研究了一种新型鏻盐——四氟硼酸四乙基鏻（TEPBF）在乙腈（AN）、丙腈（PN）、碳酸丙烯酯（PC）和磷酸三甲酯等多种溶剂中的物理和电化学特性。 （四甲基吡啶）。我们的研究表明，TEPBF/AN 电解质表现出高溶解度 (2.15 M)、高离子电导率 (52.2 mS cm) 和宽电化学稳定性窗口 (4.7 V)，这表明 TEPBF/AN 成为传统铵盐的令人信服的替代品。 AN 用于开发高功率和高压超级电容器。我们的结果还表明，在所研究的电解质中，基于 1 M TEPBF/AN 的超级电容器具有最高的电容（24.7 F g）、优异的倍率性能、最高的能量（24.9 Wh kg）和功率密度（6752 W kg）。此外，在 3.2 V 高工作电压下进行 1000 小时浮充测试后，其电容仍保持在 75%，这明显优于使用传统铵盐的其他超级电容器。