Performance of enzymatic glucose fuel cells: a mathematical comparison of hybrid and direct electron transfer models

Abstract

Operational parameters and electron transfer mechanisms influence the performance of enzymatic glucose fuel cells. Under various conditions, including pH, temperature, overpotential, substrate concentrations, and cell potential, the processes of Direct Electron Transfer (DET) and hybrid Direct Electron Transfer -mediated electron transfer (DET–MET) are modeled and compared through numerical modeling and analysis. The hybrid model is developed based on the competition pathways. Over the parameter ranges investigated (pH 5–9, 270–310 K, 0-0.5 M glucose), the hybrid method shows 20% greater performance than DET. MET pathways help the hybrid system exhibit a lower-activation energy route. The Hybrid model accounts for the competing reaction channels between DET and MET at the enzyme re-oxidation step. The hybrid model shows reasonable agreement with experimental data, yielding R² = 0.977 for the polarization curve and R² = 0.873 for concentration dependence. These results provide a quantitative modeling framework that can inform future designs of enzymatic glucose fuel cells (EGFCs).