A High-Power Glucose/Oxygen Biofuel Cell Operating under Quiescent Conditions

Abstract

We have developed the passive-type biofuel cell, in which two-electron oxidation of glucose and four-electron reduction of O2 occur at pH 7 in mediated bioelectrochemical processes, having the maximum power density of 5.0 mW/cm2 at 500 mV. This performance has been achieved by using a new electrolyte solution (Imidazole/HCl buffer, 2 M, pH 7), instead of the general solution (Sodium phosphate buffer, 1 M, pH 7); the maximum power density was a 3.0 mW/cm2 at the same conditions. By introducing the new electrolyte solution into our biofuel cell, we have succeeded in enhancing the catalytic current because the proton transfer into electrodes would increase compared with the phosphate buffer system.

Multi‐Enzyme Immobilized Anodes Utilizing Maltose Fuel for Biofuel Cell Applications

“…Figure a proves that the current peak at 0.34 V reaches the maximum of 21 mA cm −2 in 0.2 M of phosphate buffer concentration adjusted at pH 7. This result may be ascribed to the reduced ionic conductivity in concentrations lower than 0.2 M. In addition, the deactivation of the enzymes and the leakage of the mediator from the electrode by high ionic strength of the buffer solution over 0.2 M are the possible reasons because the shape of the voltammograms tested at 0.5 M and 1.0 M of phosphate buffer concentration changed during successive cycles of voltammetry ,,…”

“…We employed MAL, MUT, and GOx as the electrode catalysts for the bioanode which are immobilized on the same electrode base and immersed in the same PBS solution. Optimum pH and buffer solution for a single‐enzyme electrode depend simply on the enzyme,, while those for multi‐enzyme immobilized electrode depend on multiple factors. Figure shows the buffer concentration and pH dependency of current response in a 25 mM maltose solution for the multi‐enzyme immobilized CNT/TX/CF bioanodes.…”

Exploring Π-conjugated carbon nanomaterials for biomedical applications

“…The maximal power output (P max ) density is 2.27 ± 0.11 mW cm -2 (n=3), which is the highest value ever reported for glucose-based EBFCs. It is superior to the previously reported high performing EBFCs using a graphene electrode134 and a carbon nanotube based electrode,104 as well as other carbon electrodes 243. Figure 6-12c shows a bellshaped dependence of P max on glucose concentration at an optimal concentration of ~30 mM.…”

Flexible and transparent biological electric power sources based on nanostructured electrodes

“…In any case, most of the BFCs already developed achieve operating voltages of 0. 2 -0.3 V (Shleev, 2017), being able to power low energy consumption electronics; on the other hand, stacking of cells will be needed to achieve sufficient voltage to power higher energy consumption electronic devices (Sakai et al, 2009). …”