Measuring the Capacitance of Carbon in Ionic Liquids: From Graphite to Graphene
Measuring the Capacitance of Carbon in Ionic Liquids: From Graphite to Graphene
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DOI：
10.1021/acs.jpcc.3c08269
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发表时间：
2024-02
期刊：
影响因子：
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通讯作者：
Jing Yang;A. Papaderakis;Ji Soo Roh;A. Keerthi;R. W. Adams;M. Bissett;Boya Radha;Robert A. W. Dryfe
中科院分区：
文献类型：
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作者：
Jing Yang;A. Papaderakis;Ji Soo Roh;A. Keerthi;R. W. Adams;M. Bissett;Boya Radha;Robert A. W. Dryfe
碳/离子液体界面的物理电化学支撑着电化学储能、离子电子设备和润滑等广泛应用中发生的过程。阐明碳/电解质界面的电荷存储机制将有助于更好地理解此类系统的工作原理。在此，我们探测了模型碳系统（从单层石墨烯到石墨）和离子液体 1-乙基-3-甲基咪唑鎓双（三氟甲基磺酰基）亚胺（EMIM-TFSI）之间形成的电化学双层中存储的电荷。研究了石墨烯层数对界面总电容的影响。我们证明，在纯 EMIM-TFSI 和中等电位偏压下，石墨烯和石墨的电子特性控制着界面的整体电容，而电解质对后者的贡献不太显着。在 EMIM-TFSI 与不同相对介电常数溶剂的混合物中，电解质离子和溶剂分子之间复杂的相互作用显示出影响界面处存储的电荷，这在某些条件下克服了相对介电常数的影响。这项工作为室温离子液体和碳材料之间界面的电化学双层结构的不断发展的主题提供了额外的实验见解。
The physical electrochemistry of the carbon/ionic liquids interface underpins the processes occurring in a vast range of applications spanning electrochemical energy storage, iontronic devices, and lubrication. Elucidating the charge storage mechanisms at the carbon/electrolyte interface will lead to a better understanding of the operational principles of such systems. Herein, we probe the charge stored at the electrochemical double layer formed between model carbon systems, ranging from single-layer graphene to graphite and the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI). The effect of the number of graphene layers on the overall capacitance of the interface is investigated. We demonstrate that in pure EMIM-TFSI and at moderate potential biases, the electronic properties of graphene and graphite govern the overall capacitance of the interface, while the electrolyte contribution to the latter is less significant. In mixtures of EMIM-TFSI with solvents of varying relative permittivity, the complex interplay between electrolyte ions and solvent molecules is shown to influence the charge stored at the interface, which under certain conditions overcomes the effects of relative permittivity. This work provides additional experimental insights into the continuously advancing topic of electrochemical double-layer structure at the interface between room temperature ionic liquids and carbon materials.