Physical Modeling of the Enzymatic Glucose-Fuelled Fuel Cells

Abstract

An enzymatic glucose biofuel cell uses glucose as fuel and enzymes as biocatalyst, to transform biochemical energy into electrical energy. An analytical modelling of an enzymatic biofuel cell should be used, while developing fuel cell, to estimate its various enzymatic parameters, to obtain the highest voltage feasibly. The analytical model was developed, and the open circuit voltage (OCV) calculated by the model for various parameters of the fuel cell is in agreement with the experimental results. The OCV is interpreted by using this model, based on theoretical consideration of ions transportation in the solution. The generation and consumptions of the ions near the electrodes were defined in the model by exponential approximations, with different depletion coefficients. The model reveals that increasing the rates of hydrogen ions generation and (or) consumption by enzyme or chemical reactions leads to a higher value of OCV. The model points that the OCV is saturated with a glucose concentration and increased logarithmically with a surface enzyme concentration. Hence, a low glucose concentration is sufficient to obtain adequate OCV, on the one hand, but it can be increased by increasing electrode surface porosity, on the other hand. This model can be expanded to include time and close circuit voltage.

Current-Voltage Modeling of the Enzymatic Glucose Fuel Cells

“…The result is similar to [8]. Here c L is the hydrogen ions concentration at the point x = L between the anode and electrolyte reservoir.…”

“…The model presented here bases on experimental results with direct electron transfer fuel cell that were reported at [8]. The model includes two parallels plane each other electrodes.…”

“…The cathode is exposed to air and the porous cathode allows oxygen to pass. On the cathode, oxygen reacts chemically with the electrons from the external circuit and with the hydrogen ions from the electrolyte to yield water [8]. Michaelis-Menten equation [25] for rate of a volume hydrogen ions generationg 01 was adapted [8] to surface g 1S (Equation (1)) hydrogen ions generation …”

“…From Equations (5) (13) with boundary conditions (6,7,8,11) the hydrogen ions concentration in region (0 < x < L) can be obtain as:…”