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Sustainable Carbon/Carbon Supercapacitors Operating Down to −40 °C in Aqueous Electrolyte Made with Cholinium Salt
Author(s) -
Abbas Qamar,
Béguin François
Publication year - 2018
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.201701957
Subject(s) - supercapacitor , electrolyte , aqueous solution , carbon fibers , electrochemistry , conductivity , capacitance , salt (chemistry) , inorganic chemistry , chemistry , materials science , chemical engineering , electrode , organic chemistry , composite material , composite number , engineering
Cholinium chloride at a concentration of 5 mol kg −1 in water is proposed as a low‐cost and environmentally friendly aqueous electrolyte, enabling extension of the operating range of carbon/carbon supercapacitors (SCs) down to −40 °C. This solution has a pH close to neutrality (pH 6.1) and high conductivity of 88 mS cm −1 at 24 °C. The supercapacitors demonstrate a high capacitance of 126 F g −1 (per mass of one electrode) and long life span at voltages up to 1.5 V. At −40 °C, the carbon/carbon SCs display excellent electrochemical characteristics with only slightly reduced capacitance of 106 F g −1 and negligible ohmic losses. As compared to previous works, where antifreezing additives were introduced in traditional neutral electrolytes, the low solubility of the salt and related poor conductivity of the solution is no longer an issue, which makes cholinium salt aqueous solutions very promising for SCs operating at sub‐ambient temperature conditions.