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Hydrogel–Polymer Electrolyte for Electrochemical Capacitors with High Volumetric Energy and Life Span
Author(s) -
Gajewski Piotr,
Béguin Francois
Publication year - 2020
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201903077
Subject(s) - electrolyte , separator (oil production) , polyolefin , materials science , carboxymethyl cellulose , chemical engineering , electrochemistry , contact angle , polymer , wetting , membrane , pulmonary surfactant , polypropylene , microfiber , polymer chemistry , composite material , sodium , chemistry , layer (electronics) , electrode , biochemistry , physics , engineering , metallurgy , thermodynamics
AC/AC (AC=activated carbon) electrochemical capacitors (ECs) were designed with a 1 mol L −1 lithium sulfate hydrogel– polymer electrolyte (HPE) based on carboxymethyl cellulose sodium salt (CMC). The electrochemical performance of the ECs was compared with that of cells composed of common separators such as a polyolefin membrane (Celgard 3501, polypropylene separator coated by surfactant) and a glass microfiber membrane (Whatman GF/A). The ECs with Celgard 3501 and home‐made CMC‐HPE demonstrated a higher volumetric energy than that with Whatman GF/A. However, after 120 h of floating at 1.5 V, the capacitance of the EC with Celgard 3501 decreased dramatically by 25 %, whereas with CMC‐HPE and Whatman GF/A, the decrease was only 4 and 6 %, respectively. Post‐mortem observations of the Celgard 3501 separator after floating suggested that the surfactant layer was removed, which caused a decrease of separator wettability, as confirmed by the slow evolution of the electrolyte contact angle on its surface. Hence, CMC‐HPE is a very attractive option to develop aqueous‐electrolyte‐based ECs with an excellent life span and high volumetric energy density.