Dense Charge Accumulation in MXene with a Hydrate-Melt Electrolyte
Dense Charge Accumulation in MXene with a Hydrate-Melt Electrolyte
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DOI：
10.1021/acs.chemmater.9b01334
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发表时间：
2019-07-23
影响因子：
8.6
通讯作者：
Yamada, Atsuo
中科院分区：
文献类型：
--
作者：
Kim, Kijae;Ando, Yasunobu;Yamada, Atsuo
电化学双电层电容器是一类重要的电化学储能器件。水的EDL电容器显示出作为具有高得多的功率的廉价设备的巨大潜力;然而，它们的能量密度受到水的窄电化学窗口（1.23 V）和电极的小比容量的严重限制。在这里，我们开发了一种基于高浓度Li+水电解质（水合物熔体）和二维碳化钛MXene电极的高压水性超级电容器。实验和理论分析揭示了致密的水合Li+的存在下，在层间空间的深度充电MXene，这是实现了宽的电化学窗口的水合物熔融电解质。水合物熔融电解质与大电容MXene Ti 2CTx一起提高了水性锂离子超级电容器的性能，为先进的水性电容器提供了一种有前途的策略。
Electrochemical double-layer (EDL) capacitors operating at high charge/discharge rates are an important class of electrochemical energy storage devices. Aqueous EDL capacitors show great potential for use as inexpensive devices with much higher power; however, their energy density is severely limited by the narrow electrochemical window of water (1.23 V) and the small specific capacity of the electrodes. Here, we develop a high voltage aqueous supercapacitor based on a highly concentrated Li+ aqueous electrolyte (hydrate melt) and a two-dimensional titanium carbide MXene electrode. Experimental and theoretical analyses reveal the existence of dense hydrated Li+ in the interlayer space of the deeply charged MXene, which is realized by the wide electrochemical window of a hydrate-melt electrolyte. The hydrate-melt electrolyte together with the large capacitance MXene Ti2CTx improves the performance of an aqueous lithium-ion supercapacitor, offering a promising strategy for advanced aqueous capacitors.