Intermediate Temperature Fuel Cell with Amorphous Indium Doped Tin Phosphate Thin Film Electrolyte

Abstract: The polymer electrolyte membrane fuel cells (PEMFCs) for vehicle and portable application are faced with challenges in reducing cost and the system volume. The need of low temperature operation and humidification are the root causes of the challenge. The development of electrolyte membranes capable to operate in intermediate temperatures of 200 ~ 400 ºC without humidification is crucially required to overcome the challenges since such fuel cell provides a chance to reduce or remove Pt in electrode and no need of humidification results in simple system. In this paper, we report the first successful fabrication of fuel cell based on fully dense amorphous Sn0.9In0.1P2O7 (SIPO) proton conducting thin film electrolyte membrane formed by sputtering. The obtained thin film electrolyte exhibits extremely low area specific resistance (ASR) of 0.04 ohm＆ #8729;cm2 without any additional humidification at 200°C. The densification degree of the thin film electrolyte was confirmed through the observation of microstructure and open circuit voltage (OCV) higher than 0.9V in the fuel cells based on the thin film electrolyte. The thin film fuel cell yielded a peak power density of 44 mWcm-2 with electrolyte thickness of 180 nm at 200ºC.