Effect of carbon surface on degradation of supercapacitors in a negative potential range
Effect of carbon surface on degradation of supercapacitors in a negative potential range
复制标题
DOI：
10.1016/j.jpowsour.2020.228042
复制
发表时间：
2020-05
影响因子：
9.2
通讯作者：
Rui Tang;Masanori Yamamoto;K. Nomura;E. Morallón;D. Cazorla-Amorós;H. Nishihara;T. Kyotani
中科院分区：
文献类型：
--
作者：
Rui Tang;Masanori Yamamoto;K. Nomura;E. Morallón;D. Cazorla-Amorós;H. Nishihara;T. Kyotani
超级电容器的稳定性是其在高温、高压下使用和长期耐用的关键因素。为了提高超级电容器的稳定性，需要了解其退化机理。在这项工作中，碳电极在负电位范围内的降解位点进行了研究，在两个常见的有机电解质：1 M Et4NBF4溶解在碳酸丙烯酯和乙腈。为了阐明广泛的碳材料的共同因素，我们研究了八种碳材料，包括活性炭，炭黑，沸石模板碳（高比表面积和大量的碳边缘位置）和石墨烯介孔海绵（高比表面积和少量的碳边缘位置）。通过氮的物理吸附和高达1800 °C的高灵敏度程序升温脱附将它们的表面结构区分为两个区域：碳基面和边缘位置。与正电位区的降解不同，负电位区的初始降解反应主要发生在碳的基面上，而不是边缘部位。这一发现得到了理论计算的证实。
The stability of supercapacitors is the key factor for their use under high temperature, high voltage and long-term durability. To improve the supercapacitor stability, there is a need to understand the degradation mechanism. In this work, the degradation sites in a carbon electrode at negative potential range are investigated in two common organic electrolytes: 1 M Et4NBF4dissolved in propylene carbonate and in acetonitrile. To elucidate the common factor over a wide range of carbon materials, we examined eight kinds of carbon materials including activated carbons, carbon blacks, zeolite-template carbon (high surface area and a large amount of carbon edge sites) and graphene mesosponge (high surface area and a little amount of carbon edge sites). Their surface structures are distinguished into two regions: carbon basal planes and edge sites by nitrogen physisorption and high-sensitivity temperature-programmed desorption up to 1800 °C. Unlike the degradation at positive potential range, initial degradation reactions at negative potential range occur mainly on the carbon basal planes rather than the edge sites. This finding is corroborated by the theoretical calculation.