Carbon nanotube dispersed conductive network for microbial fuel cells

Abstract

Microbial fuel cells (MFCs) are promising devices for capturing biomass energy. Although they have recently attracted considerable attention, their power densities are too low for practical use. Increasing their electrode surface area is a key factor for improving the performance of MFC. Carbon nanotubes (CNTs), which have excellent electrical conductivity and extremely high specific surface area, are promising materials for electrodes. However, CNTs are insoluble in aqueous solution because of their strong intertube van der Waals interactions, which make practical use of CNTs difficult. In this study, we revealed that CNTs have a strong interaction with Saccharomyces cerevisiae cells. CNTs attach to the cells and are dispersed in a mixture of water and S. cerevisiae, forming a three-dimensional CNT conductive network. Compared with a conventional two-dimensional electrode, such as carbon paper, the three-dimensional conductive network has a much larger surface area. By applying this conductive network to MFCs as an anode electrode, power density is increased to 176 μW/cm², which is approximately 25-fold higher than that in the case without CNTs addition. Maximum current density is also increased to approximately 8-fold higher. These results suggest that three-dimensional CNT conductive network contributes to improve the performance of MFC by increasing surface area.

Key findings

• ▸CNTs form a strong interaction with S. cerevisiae cells, creating a three-dimensional conductive network.
• ▸The three-dimensional conductive network increases the electrode surface area, leading to a 25-fold higher power density compared to a conventional two-dimensional electrode.
• ▸The power density of MFCs with the CNT conductive network is 176 μW/cm², significantly higher than without CNTs addition.

Keywords

Identifiers

DOI

10.1063/1.4894259

Journal

Applied Physics Letters

Year

2014