Double-layer capacitors ionic liquid applications

Makoto, U. Application of ionic liquids to double-layer capacitors. In Electrochemical Aspects of Ionic Liquids. John Wiley Sons, NJ 2005, ISBN 9780471648512. 

APPLICATION OF IONIC LIQUIDS TO DOUBLE-LAYER CAPACITORS... 

Ue, M., M. Takeda, T. Takahashi, and M. Takehara. 2002. Ionic liquids with low melting points and their application to double-layer capacitor electrolytes. Electrochemical and Solid-State Letters 5 A119-A121. 

Ue, M., M. Takeda, A. Toriumi, A. Kominato, R. Hagiwara, and Y. Ito. 2003. Application of low-viscosity ionic liquid to the electrolyte of double-layer capacitors. Journal of the Electrochemical Society 150 A499-A502. 

Sato, T., G. Masuda, and K. Takagi. 2004. Electrochemical properties of novel ionic liquids for electric double layer capacitor applications. Electrochimica Acta 49 3603-3611. 

Oleg Borodin works as a scientist at the Electrochemistry Branch of the Army Research Laboratory, Adelphi, MD since 2011. After obtained a Ph.D. degree in Chemical Engineering in 2000 he worked in the area of multiscale modeling of liquid, ionic liquid and polymer electrolytes for battery and double layer capacitor applications, modeling of energetic composite materials, polymers in solutions, and polymer nanocomposites. He coauthored more than a hundred publications and four book chapters. His modeling efforts focus on the scales from electronic to atomistic and mesoscale. 

Ionic Liquids for the Electric Double Layer Capacitor Applications... 

The value of the resistance that is most relevant to the power density performance of an EDLC, the cell resistance, increased in the order of BF4, Pp6 and TFSI. Of the ionic liquids tested, MEMP-BF4 and DEME-BF4, both of which have a methoxyethyl group on nitrogen atom, showed the highest durability in a continuous charging life test. We conclude that ionic liquids containing the tetrafluoroborate anion have the best performance and stability for electric double layer capacitor applications. 

In the drive towards expanding the range of useful ionic liquids (ILs), with suitably low viscosities, sufficient stability, and conductivity for electrochemical uses, phosphonium-based ionic liquids (PILs) are exceptionally promising compounds. Due to the high thermal and electrochemical stabilities of PILs compared to ammonium-based ILs (allq l-ammonium, imidazolium, pyridinium, pyrrolidinium, and piperidinium compounds), phosphonium salts have been especially considered for applications as electrolytes. Their properties (both thermal and electrochemical stabilities) are in fact crucial to improve safety, durability, power and energy densities of electrochemical devices such as electric double layer capacitors. 

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