1-Allyl-3-methylimidazolium-based ionic liquids employed as suitable electrolytes for high energy density supercapacitors based on graphene nanosheets electrodes
1-Allyl-3-methylimidazolium-based ionic liquids employed as suitable electrolytes for high energy density supercapacitors based on graphene nanosheets electrodes
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DOI：
10.1016/j.molliq.2017.11.078
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发表时间：
2018
影响因子：
6
通讯作者：
Ramzi Zarrougui;Rahma Hachicha;Refka Rjab;Ouassim Ghodbane
中科院分区：
文献类型：
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作者：
Ramzi Zarrougui;Rahma Hachicha;Refka Rjab;Ouassim Ghodbane
采用专门的合成路线合成了一系列新型低粘度1-烯丙基-3-甲基咪唑离子液体。对所得分子无溶剂离子液体（真离子液体）的物理化学性质进行了研究，并对阴离子组分进行了系统的讨论。本文研究了六种电解质，包括一种平面结构阴离子（DCA-）和五种非平面结构阴离子（PF 6-、TFSI-、BF 4-、TFA-和OTf-）。所制备的离子液体用作基于石墨烯纳米片（GNS）电极的对称电化学双层电容器（EDLC）的绿色电解质。EDLC器件的比电容范围为135至228 F·g− 1，能量密度范围为41至115 Wh·kg− 1。在大电池电压窗口（3- 4V）上1000次充电/放电循环后达到94%的电化学稳定性，具有准理想的电容行为。在所研究的离子液体中，1-烯丙基-3-甲基咪唑双氰胺（AMIM-DCA）表现出最高的比电容和最大的能量密度。这种性能归因于基于通道的2-D石墨烯网络与AMIM-DCA的平面结构之间的相容性。由此产生的AMIM-DCA/GNS界面有利于在电荷存储期间电解质离子的可逆吸附/脱附过程。因此，所研究的EDLC电池是高容量和高可靠性储能应用的有希望的候选者。
The preparation of a series of novel low viscosity 1-allyl-3-methylimidazolium ionic liquids (ILs) is performed following dedicated synthetic routes. The physico-chemical properties of resulting molecular solvent-free ILs (true ILs) are investigated and discussed systematically toward the anion constituents. Herein, six electrolytes are studied including one planar structured anion (DCA−) and five anions presenting non-planar structures (PF6−, TFSI−, BF4−, TFA−and OTf−). The as-prepared ILs are employed as green electrolytes for symmetric electrochemical double layer capacitors (EDLCs) based on graphene nanosheets (GNS) electrodes. The EDLC devices deliver specific capacitances ranging from 135 to 228 F·g− 1, and suitable energy densities, ranging from 41 to 115 Wh·kg− 1. An electrochemical stability of 94% is reached upon 1000 charge/discharge cycles over a large cell voltage window (3–4 V) with a quasi-ideal capacitive behaviour. Among the studied ILs, 1-allyl-3-methylimidazolium dicyanmide (AMIM-DCA) exhibit the highest specific capacitance and the maximum energy density. Such a performance is attributed to the compatibility between the channel-based 2-D graphene network and the planar structure of AMIM-DCA. The resulting AMIM-DCA/GNS interface facilitates the reversible adsorption/desorption process of electrolyte ions during the charge storage. Accordingly, the studied EDLC cells are promising candidates for high-capacity and high-reliability energy-storage applications.