Anode ink formulation for a fully printed flexible fuel cell stack

• Published in: Flexible and printed electronics 2020-06, Vol.5 (2), p.25002
• Main Authors: Hakola, Liisa, Parra Puerto, Andres, Vaari, Anu, Maaninen, Tiina, Kucernak, Anthony, Viik, Saara, Smolander, Maria
• Format: Article
• Language: English
• Subjects: anode; catalyst; flexible; formulation; fuel cell; ink; inkjet; print; stack
• ISSN: 2058-8585; 2058-8585
• DOI: 10.1088/2058-8585/ab7e16

In fuel cells the underlying reactions take place at the catalyst layers composed of materials favoring the desired electrochemical reactions. This paper introduces a formulation process for a catalyst inkjet ink used as an anode for a fully printed flexible fuel cell stack. The optimal ink formulation was 2.5 wt% of carbon-platinum-ruthenium mixture with 0.5% Nafion concentration in a diacetone alcohol solvent vehicle. The best jetting performance was achieved when 1 wt% binder was included in the ink formulation. Anodes with resistivity of approximately 0.1 Ω cm were inkjet printed, which is close to the commercial anode resistivity of 0.05 Ω cm. The anodes were used in fuel cell stacks that were prepared by utilizing only printing methods. The best five-cell-air-breathing stack showed an open circuit potential under H2/air conditions of 3.4 V. The peak power of this stack was 120 µW cm−2 at 1.75 V, with a resistance obtained from potentiostatic impedance analysis of 295 Ohm cm2. The printed electrodes showed a performance suitable for low-performance solutions, such as powering single-use sensors.