Highly Durable, Self-Standing Solid-State Supercapacitor Based on an Ionic Liquid-Rich lonogel and Porous Carbon Nanofiber Electrodes
Highly Durable, Self-Standing Solid-State Supercapacitor Based on an Ionic Liquid-Rich lonogel and Porous Carbon Nanofiber Electrodes
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DOI：
10.1021/acsami.7b07479
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发表时间：
2017-10-04
影响因子：
9.5
通讯作者：
Kalra, Vibha
中科院分区：
文献类型：
--
作者：
Simotwo, Silas K.;Chinnam, Parameswara Rao;Kalra, Vibha
通过将富含离子液体（IL）的离子凝胶(95 wt % IL （l-efhyl-3”甲基咪唑二（txifluorom甲基磺酰基）亚胺）和5 wt %甲基纤维素（一种聚合物基质）结合到高度互连的3-D活性炭纳米纤维（CNF）电极中，制备了高性能、自立型固态超级电容器。在25℃下，离子凝胶的存储模量为5 MPa，离子电导率为5.7 mS cm(-1)，具有较强的力学性能。通过静电纺丝技术获得的高表面积cnf电极(2282 m(2) g(-1))，在热解和KOH活化过程中均表现出分层孔隙度。CNF电极的多孔结构促进了柔软但机械耐用的离子凝胶膜的易于渗透，从而使多孔纳米纤维和凝胶电解质界面之间的紧密接触成为可能。该超级电容器表现出良好的电容特性，包括153 F g（-1）的重量电容。具有65 W h kg（-1）的高比能密度和高循环稳定性，在1 Ag-1条件下充放电2万次后电容衰减仅为4%。此外，在电极质量负载分别为3.20和5.10 mg cm（-2）时，凝胶IL细胞的器件级面电容分别为122和151 mF cm（-2）。
A high-performance, self-standing solid-state supercapacitor is prepared by incorporating an ionic liquid (IL)-rich ionogel made with 95 wt % IL (l-efhyl-3"methylimidazolium bis(txifluoromethylsulfonyl)imide) and 5 wt % methyl cellulose, a polymer matrix, into highly interconnected 3-D activated carbon nanofiber (CNF) electrodes. The ionogel exhibits strong mechanical properties with a storage modulus of 5 MPa and a high ionic conductivity of 5.7 mS cm(-1) at 25 oC. The high-surface-area CNF-based electrode (2282 m(2) g(-1) ), obtained via an electrospinning technique, exhibits hierarchical' porosity generated both in situ during pyrolysis and ex situ via KOH activation. The porous architecture of the CNF electrodes facilitates the facile percolation of the soft but mechanically durable ionogel film, thereby enabling intimate contact between porous nanofibers and the gel electrolyte interface. The supercapacitor demonstrates promising capacitive characteristics, including a gravimetric capacitance of 153 F g(-1) ,. a high specific energy density of 65 W h kg(-1) , and high cycling stability, with a capacitance fade of only 4% after 20 000 charge-discharge-cycles at 1 Ag-1 . Moreover, device-level areal capacitances for the gel IL cell of 122 and 151 mF cm(-2) are observed at electrode mass loadings of 3.20 and 5.10 mg cm(-2) , respectively.