Sodium borohydride as an additive to enhance the performance of direct ethanol fuel cells

✍ Scribed by Lianqin Wang; Valentina Bambagioni; Manuela Bevilacqua; Claudio Bianchini; Jonathan Filippi; Alessandro Lavacchi; Andrea Marchionni; Francesco Vizza; Xiang Fang; Pei Kang Shen

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 571 KB
• Volume: 195
• Category: Article
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2010.06.101

✦ Synopsis

The effect of adding small quantities (0.1-1 wt.%) of sodium borohydride (NaBH 4 ) to the anolyte solution of direct ethanol fuel cells (DEFCs) with membrane-electrode assemblies constituted by nanosized Pd/C anode, Fe-Co cathode and anion-exchange membrane (Tokuyama A006) was investigated by means of various techniques. These include cyclic voltammetry, in situ FTIR spectroelectrochemistry, a study of the performance of monoplanar fuel cells and an analysis of the ethanol oxidation products. A comparison with fuel cells fed with aqueous solutions of ethanol proved unambiguously the existence of a promoting effect of NaBH 4 on the ethanol oxidation. Indeed, the potentiodynamic curves of the ethanol-NaBH 4 mixtures showed higher power and current densities, accompanied by a remarkable increase in the fuel consumption at comparable working time of the cell. A 13 C and 11 B { 1 H}NMR analysis of the cell exhausts and an in situ FTIR spectroelectrochemical study showed that ethanol is converted selectively to acetate while the oxidation product of NaBH 4 is sodium metaborate (NaBO 2 ). The enhancement of the overall cell performance has been explained in terms of the ability of NaBH 4 to reduce the PdO layer on the catalyst surface.