Fabrication of novel phosphotungstic acid functionalized mesoporous silica composite membrane by alternative gel-casting technique

• Published in: Journal of power sources Vol. 221; pp. 318 - 327
• Main Authors: Zhang, Lan, He, Hong Quan, S/O Abdul Rasheed, Raj Kamal, Zhou, Wei Jiang, Xue, Yan Hong, Ding, Ovi Lian, Chan, Siew Hwa
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2013; Elsevier
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Direct methanol fuel cell; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Gel-casting; High-temperature proton exchange membranes; Materials; Mesoporous silica; Phosphotungstic acid; Gel-casting; High-temperature proton exchange membranes; Phosphotungstic acid; Direct methanol fuel cell; Mesoporous silica; Water; Costs; Fourier transformation; High temperature; Small angle X ray scattering; Porous material; IV-VI compound; Composite material; Humidification; Fourier-transformed infrared spectrometry; Peak power; Proton exchange; Methanol; Tungstophosphoric acid; Multichip module; Thermogravimetry; Alcohol fuel cells; Forming; Mesoporosity; Casting; Electrolyte; Silicon oxides; Microstructure
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2012.07.131

A simple and cost-effective gel-casting technique has been developed to fabricate phosphotungstic acid (HPW) supported on mesoporous silica (MCM-41) electrolyte membrane (HPW/MCM-41) for direct methanol fuel cells (DMFCs). The effect of HPW loading on the stability of MCM-41 structure has been analyzed by small-angle X-ray scattering (SAXS), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) techniques. In particular, the effect of solid state loading and HPW loading on the microstructure, water gain ratio, swelling ratio and conductivity of the HPW/MCM-41 membranes have been studied in detail. The results showed that a large proportion of loaded HPW is anchored in the mesoporous silica matrix, forming an effective proton conduction pathway. The results also showed that the composite membrane can operate successfully at temperatures below 200 °C for a long duration, based on the TGA curve of organic network formed during the gelation stage. The single cell assembled from HPW/MCM-41 membrane with 65 wt.% HPW loading gives a peak power of 101 mW cm−2 in methanol/air at 150 °C without any humidification. ► HPW/MCM-41 composite membranes have been fabricated by a gel-casting technique. ► HPW/MCM-41 composite membranes can operate stably below 200 °C. ► A single cell can be assembled using the HPW/MCM-41 membrane. ► A maximum output power density of 101 mW cm−2 in MeOH/air at 150 °C was observed.