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Capacitance Evolution of Electrochemical Capacitors with Tailored Nanoporous Electrodes in Pure and Dissolved Ionic Liquids
Author(s) -
Mysyk R.,
Ruiz V.,
RaymundoPiñero E.,
Santamaria R.,
Béguin F.
Publication year - 2010
Publication title -
fuel cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.485
H-Index - 69
eISSN - 1615-6854
pISSN - 1615-6846
DOI - 10.1002/fuce.201000023
Subject(s) - nanoporous , ionic liquid , capacitor , electrochemistry , capacitance , materials science , electrode , ionic bonding , chemical engineering , inorganic chemistry , ion , nanotechnology , chemistry , electrical engineering , voltage , engineering , organic chemistry , catalysis
Abstract A homologous series of ionic liquids (IL) with 1‐alkyl‐3‐methylimidazolium cations of different lengths of alkyl chain was used to study the effect of cation size on the capacitive response of two carbons with a tailored pore size distribution. The results reveal a clear ion‐sieving effect in pure ILs, while the effect is heavily mitigated for the same salts used in solution, most likely due to somewhat stronger geometrical flexibility of dissolved ions. For the electrode material showing the ion‐sieving effect in solution, the gravimetric capacitance values are higher than in pure ILs. The dissimilarity of capacitance values between pure and dissolved ILs with ion‐sieving carbons highlights their respective advantages and disadvantages in terms of energy density: whereas pure ILs can potentially provide a larger working voltage window, the corresponding dissolved salts can access smaller pores, mostly contributing to higher capacitance values.