Ultra-high salt concentration has recently been reported to extend the kinetic stability of aqueous electrolytes up to 3 V. However, the low ionic conductivity of these systems makes them unsuitable for high power devices such as supercapacitors. In this study, an 8 mol kg^-1 NaTFSI aqueous electrolyte is reported that displays high stability of 1.8 V on activated carbon during a stringent stability test and conductivity of 48 mS cm^-1 at 20 °C, the latter being comparable to the one of state-of-the-art acetonitrile-based non-aqueous electrolytes. A 1.8 V carbon/carbon supercapacitor employing 8 mol kg^-1 NaTFSI displays a high maximum energy density of 14.4 Wh kg^-1 on the activated carbon mass level and stable cycling for 100,000 cycles. By addition of the redox additive potassium iodide to the electrolyte, the maximum specific energy could be increased to an extremely high value of 37.8 Wh kg^-1, comparable to the performance of the current generation of commercial non-aqueous supercapacitors.

中文翻译：

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基于NaTFSI的高压水性超级电容器

最近已报道超高盐浓度可将水性电解质的动力学稳定性扩展至3V。但是，这些系统的低离子电导率使其不适用于超级电容器等大功率设备。在这项研究中，据报道有8 mol kg ^-1的NaTFSI水性电解质，在严格的稳定性测试过程中在活性炭上显示出1.8 V的高稳定性，在20°C时的电导率为48 mS cm ^-1，后者可与之媲美。最先进的乙腈基非水电解质。采用8 mol kg ^-1 NaTFSI的1.8 V碳/碳超级电容器显示出14.4 Wh kg ^-1的高最大能量密度在活性炭质量水平上稳定运行了100,000个循环。通过将氧化还原添加剂碘化钾添加到电解质中，可以将最大比能提高到37.8 Wh kg ^-1的极高值，与当前的商用非水超级电容器的性能相当。