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Mathematical Modeling and Experimental Validation of

Direct Ethanol Fuel Cell

Jyoti Goel, Sudhasatwa Basu*

Department of Chemical Engineering, Indian Institute of Technology Delhi,

New Delhi 110016, India

Abstract

In the present work a comprehensive one dimensional steady state mathematical model is developed to study the behaviour of direct ethanol fuel cell (DEFC). Model considers all the relevant mass transfer relations and electro-chemical phenomena in electrodes and electrolyte of a DEFC. The expression for electro-chemical oxidation of ethanol in anode catalyst layer is obtained by considering the multistep bi-functional ethanol oxidation reaction (EOR) mechanism. Model is developed by taking into account the concentration profile all species involed in EOR, ORR and proton transfer in anode, cathode and PEM segments of DEFC [1]. The expression for anode and cathode over potential is developed by considering diffusion and convective effects for ethanol transport, hydraulic permeation and diffusion of gas mixture in the cathode side of the cell. Overall polarization of DEFC is obtained by systematically addressing the phenomena, such as, ethanol cross over and mixed potential effect, limiting current behaviour and variation in anode and cathode over-potential in the catalyst layer [2]. According to the model predictions the increase in ethanol fuel concentration leads to higher ethanol crossover rate, higher parasitic current and mixed potential resulting in the decrease in current density and peak power density of DEFC. The plots of limiting current density, crossover flux, cathode over-potential, open circuit voltage, Faradaic efficiency, and ethanol cross over efficiency for ethanol concentrations are obtained using the mathematical model. The DEFC performance is predicted well by the model for experimental data of Pt-Re-Sn/MCN (20:5:15), Pt-Ru/MCN (20:20) and Pt-Re-Sn/C (20:5:15) anode catalysts [3].

[1] Andreadis G, Song S., Tsiakaras P., J Power Sources 2006; 157: 657-665

[2] Suresh N. S., Jayanti S., Int. J. Hydrogen Energy 2011: 36:15648-14658

[3] Goel J and Suddhasatwa Basu, Intl J. Hydrogen Energy accepted online (2014) DOI: 10.1016/j.ijhydene.2014.01.203

 

∗ Corresponding author: e-mail sbasu@iitd.ac.in; Tel +91 11 26591035; Fax +91 11 26581120

Presented by corresponding author

 

Anode catalyst layer, cathode catalyst layer, ethanol cross over, direct ethanol fuel cell