Carbon oxygenated functional groups and active sites play an important role in the interactions with the electrolytes in aqueous supercapacitors. For the first time, correlations between each type of O-surface groups and electrochemical performance are established by means of thermodesorption coupled with mass spectrometry (TPD-MS). A set of five activated carbons and one soft-salt templated carbon, were studied in three different pH electrolytes, 1 M H₂SO₄, 1 M KOH and 1 M Na₂SO₄. Linear correlations between surface groups and capacitance were found: acidic groups such as carboxylic acid and phenol-ether groups improve capacitance, whereas carbonyl-quinone groups are detrimental. Moreover, active surface area (ASA) is for the first time measured for activated carbons thanks to a new protocol, which minimises material burn-off during oxygen chemisorption. In addition, a new approach consisting in the quantification of the ASA is proposed. It has been highlighted that certain active sites are linearly correlated to an improvement of capacitance. Although the oxygen surface groups and ASA improve the capacitance via pseudo-capacitance phenomena, the capacitive mechanisms, governed by the porosity of the activated carbons, are shown to be predominant. Among all materials, the soft-salt templated carbon gives the best electrochemical performance. Indeed, it combines a large quantity of carboxylic acid and phenol-ether surface groups as well as appropriate ASA. Moreover, it has a high specific surface area (2556 m²·g^-1) and optimal pore size (0.89 nm). All these characteristics, provide a high capacitance, a high rate capability and a high capacitance retention after 10,000 cycles.

中文翻译：

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通过 TPD-MS 定量分析活性炭官能团和活性表面积及其对超级电容器性能的影响


碳氧官能团和活性位点在与水性超级电容器中电解质的相互作用中起着重要作用。首次通过热脱附-质谱联用 （TPD-MS） 建立了每种类型的 O 表面基团与电化学性能之间的相关性。在三种不同的 pH 电解质 1M H ₂ SO ₄ 、1M KOH 和 1M Na ₂ SO 中研究了一组 5 种活性炭和 1 种软盐模板碳 ₄ 。发现表面基团和电容之间存在线性相关性：酸性基团（如羧酸和苯酚醚基团）提高了电容，而羰基醌基团则是有害的。此外，由于采用了新的协议，首次测量了活性炭的活性表面积 （ASA），该协议最大限度地减少了氧气化学过程中的材料燃烧。此外，还提出了一种包括 ASA 量化的新方法。已经强调，某些有源位点与电容的改善呈线性相关。尽管氧表面基团和 ASA 通过赝电容现象提高了电容，但由活性炭孔隙率控制的电容机制被证明是主要的。在所有材料中，软盐模板碳具有最佳的电化学性能。事实上，它结合了大量的羧酸和酚醚表面基团以及适当的 ASA。此外，它还具有高比表面积 （2556 m²·g ^-1 ） 和最佳孔径 （0.88 nm）。所有这些特性提供了高电容、高倍率能力和 10,000 次循环后的高电容保持能力。