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Title: Impurity effects on ionic-liquid-based supercapacitors

Journal Article · · Molecular Physics
 [1];  [2];  [3];  [1]
  1. Univ. of California, Riverside, CA (United States)
  2. Univ. of California, Riverside, CA (United States); East China Univ. of Science and Technology, Shanghai (People's Republic of China)
  3. Brigham Young Univ., Provo, UT (United States)
+ Show Author Affiliations

Small amounts of an impurity may affect the key properties of an ionic liquid and such effects can be dramatically amplified when the electrolyte is under confinement. Here the classical density functional theory is employed to investigate the impurity effects on the microscopic structure and the performance of ionic-liquid-based electrical double-layer capacitors, also known as supercapacitors. Using a primitive model for ionic species, we study the effects of an impurity on the double layer structure and the integral capacitance of a room temperature ionic liquid in model electrode pores and find that an impurity strongly binding to the surface of a porous electrode can significantly alter the electric double layer structure and dampen the oscillatory dependence of the capacitance with the pore size of the electrode. Meanwhile, a strong affinity of the impurity with the ionic species affects the dependence of the integral capacitance on the pore size. Up to 30% increase in the integral capacitance can be achieved even at a very low impurity bulk concentration. As a result, by comparing with an ionic liquid mixture containing modified ionic species, we find that the cooperative effect of the bounded impurities is mainly responsible for the significant enhancement of the supercapacitor performance.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Energy Frontier Research Centers (EFRC) (United States). Fluid Interface Reactions, Structures and Transport Center (FIRST)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC05-00OR22725; ERKCC61
OSTI ID:
1399241
Alternate ID(s):
OSTI ID: 1388372
Journal Information:
Molecular Physics, Vol. 115, Issue 4; ISSN 0026-8976
Publisher:
Taylor & FrancisCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 16 works
Citation information provided by
Web of Science

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Cited By (2)

Computational Insights into Materials and Interfaces for Capacitive Energy Storage journal April 2017
Wettability of ultra-small pores of carbon electrodes by size-asymmetric ionic fluids journal February 2020

Linked Research (2)

Figures / Tables (9)

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Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
25 ENERGY STORAGE
electrical double layer
energy storage
classical density functional theory
catalysis (heterogeneous)
solar (fuels)
energy storage (including batteries and capacitors)
hydrogen and fuel cells
electrodes - solar
mechanical behavior
charge transport
materials and chemistry by design
synthesis (novel materials)