POLYMER-ELECTROLYTE MEMBRANE FOR FUEL CELLS BASED ON CROSS-LINKED POLYIMIDE AND PROTIC IONIC LIQUID

• Published in: Vìsnik Dnìpropetrovsʹkogo unìversitetu. Serìâ Hìmìâ Vol. 25; no. 2; pp. 49 - 57
• Main Authors: Makhno, Stanislav М., Tarasyuk, Oksana P., Cherniavska, Tetiana V., Dzhuzha, Oleg V., Parkhomenko, Valeriy І., Rogalsky, Sergiy P.
• Format: Journal Article
• Language: English
• Published: Oles Honchar Dnipropetrovsk National University 01.01.2018
• Subjects: паливні елементи; полімер - електролітна мембрана; поліімід; протона провідність; іонна рідина
• ISSN: 2306-871X; 2313-4984
• DOI: 10.15421/081708

The aim of this research was to develop polymer-electrolyte membrane on the base of commercial polyimide Matrimid which has high proton conductivity at elevated temperatures above 100 °C. Hydrophobic ionic liquid 1-butylimidazolium bis(trifluoromethylsulfonyl)imide (BIM-TFSI) has been synthesized and used as proton conducting electrolyte. The electrical conductivity of the ionic liquid determined by electrochemical impedance method was found to have a value of 10–3 S/cm in the temperature range from 100 to 180 °С. The composite film based on Matrimid polyimide containing 70 wt % of protic ionic liquid has been prepared by casting from methylene chloride solution. Polyetheramine Jeffamine® D-2000 was used as a cross-linking agent for polyimide. According to mechanical and thermal analysis data, Matrimid/BIM-TFSI composite has tensile strength of 18 MPa and thermal degradation point of 306 °С. Electrophysical properties of polyimide film impregnated with ionic liquid was studied by two-probe technique at the frequencies of 0.1, 1.0 and 10 kHz by using immitance meter in the temperature range from 25 to 180 °С. The electrical conductivity was found to be 2.7∙10–4 S/cm at room temperature and reached the value of 1.5∙10–3 S/cm at 180 °С. Thus, in this work proton conducting membrane based on commercial polyimide has been obtained for the first time by simple method without additional sulfonation stage. Matrimid/BIM-TFSI composite membrane is promising for applications in fuel cells operating at elevated temperature without external humidification.