Ionic liquids are considered promising electrolytes for developing electric double-layer capacitors (EDLCs) with high energy density. To identify optimal operating conditions, we performed molecular dynamics simulations of N-methyl-N-propyl pyrrolidinium bis(trifluoromethanesulfonyl)imide (mppy+ TFSI−) ionic liquid confined in the interstices of vertically aligned carbon nanostructures mimicking the electrode structure. We modeled various surface charge densities as well as varied the distance between nanotubes in the array. Our results indicate that high-density ion storage occurs within the noninteracting double-layer region formed in the nanoconfined domain between charged nanotubes. We determined the specific arrangement of these ions relative to the nanotube surface and related the layered configuration to the molecular structure of the ions. The pitch distance of the nanotube array that enables optimal mppy+ TFSI− storage and enhanced capacitance is determined to be 16 Å.
Ion Storage in Nanoconfined Interstices Between Vertically Aligned Nanotubes in Electric Double-Layer Capacitors
Washington State University,
Pullman, WA 99164-2920
Manuscript received May 31, 2017; final manuscript received August 10, 2017; published online September 19, 2017. Assoc. Editor: Kevin Huang.
Dive, A., and Banerjee, S. (September 19, 2017). "Ion Storage in Nanoconfined Interstices Between Vertically Aligned Nanotubes in Electric Double-Layer Capacitors." ASME. J. Electrochem. En. Conv. Stor. February 2018; 15(1): 011001. https://doi.org/10.1115/1.4037582
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