Simulation of portable low power direct glucose fuel cell for medical implant using a COMSOL

Fuel cells can work with every fuel source to generate high-efficiency power with low emissions. Enzymatic glucose fuel cell is one of the promising low-power portable devices which can be used for medicinal implants. One of their challenges is their extremely low power and short durability. In this study, a Direct Glucose Fuel Cell (DGFC) was modeled by computational fluid dynamics using COMSOL Multiphysics® software. The performance of the fuel cell was evaluated by modeling of mass transport of reactants, products, and intermediate species, together with reaction kinetics and ohmic resistance effects. Also, concentration profiles of chemical components and the temperature distributions in each layer of DGFC have been predicted. Validation of the model was well confirmed with experimental data. The effect of anodic overpotential was significant relative to that of cathodic and ohmic overpotentials because of the complexity of the glucose electro-oxidation. The enhancement of reactants concentration, temperature, and cathode side pressure caused to improvement in the DGFC performance while the increase in membrane thickness has an adverse effect on the cell voltage.A DGFC can oxidizes glucose at anode and reduces oxygen at cathode to give electric energy through electrocatalysis (Fig. ۱A). To enhance the performance, it is necessary to reduce overpotentials and increase the turnover to. Generally, glucose would be oxidized using two electron/two proton and generate gluconolactone whereas oxygen is reduced via a four proton/four electron process to produce water. Because of continuous consumption of glucose and oxygen in physiological fluids by the metabolism, this procedure is able to support sufficient energy over the patient lifetime without any need of power supply facility. Coupling of mass transport with concentration-dependent was performed using Butler–Volmer expression in a porous gas diffusion electrode a cathode). Convective velocity was defined from Darcy’s law in the porous gas diffusion electrode, whereas diffusion is modeled using theMaxwell–Stefan equations. In this model, the mass transport of reactant, products andintermediate species in the cell, together with reaction kinetics and ohmic resistance effects in aDGFC system is investigated.The effect of glucose concentration on the cell power was investigated. Increasing of glucose concentration upto ۰.۴–۰.۶ mol dm–۳ enhance the cell power, while at higher fuel level, the cell power diminishedsignificantly. The cell power increased when theWith increasing the temperature from ۲۹۸ to ۳۱۸ K, power increases, and it did not increase at highertemperature. This can be reasonably explained by spontaneous oxidation of glucose molecules in the stronglybasic solution prior to reaching the catalyst surface, which becomes more remarkable at high temperature. Onthe other hand, the cell voltage drop occur with the increasing current density at lower temperatures but notrealized at ۳۲۸ K. Adsorption of reaction media on the catalyst surface could lead to deactivation

کلیدواژه ها:

Glucose ، Fuel Cell ، COMSOL ، Cell performance