Carbon Nano-Fiber/PDMS Composite Used as Corrosion-Resistant Coating for Copper Anodes in Microbial Fuel Cells.

Fatma Bensalah,François Buret,Naoufel Haddour,Julien Pézard,Mohsen Erouel,Kamel Khirouni

doi:10.3390/nano11113144

Abstract

The development of high-performance anode materials is one of the greatest challenges for the practical implementation of Microbial Fuel Cell (MFC) technology. Copper (Cu) has a much higher electrical conductivity than carbon-based materials usually used as anodes in MFCs. However, it is an unsuitable anode material, in raw state, for MFC application due to its corrosion and its toxicity to microorganisms. In this paper, we report the development of a Cu anode material coated with a corrosion-resistant composite made of Polydimethylsiloxane (PDMS) doped with carbon nanofiber (CNF). The surface modification method was optimized for improving the interfacial electron transfer of Cu anodes for use in MFCs. Characterization of CNF-PDMS composites doped at different weight ratios demonstrated that the best electrical conductivity and electrochemical properties are obtained at 8% weight ratio of CNF/PDMS mixture. Electrochemical characterization showed that the corrosion rate of Cu electrode in acidified solution decreased from (17 ± 6) × 103 μm y−1 to 93 ± 23 μm y−1 after CNF-PDMS coating. The performance of Cu anodes coated with different layer thicknesses of CNF-PDMS (250 µm, 500 µm, and 1000 µm), was evaluated in MFC. The highest power density of 70 ± 8 mW m−2 obtained with 500 µm CNF-PDMS was about 8-times higher and more stable than that obtained through galvanic corrosion of unmodified Cu. Consequently, the followed process improves the performance of Cu anode for MFC applications.

Highlights

These results indicate that carbon nanofiber (CNF)-PDMS layers prevent the direct a small influence of coating thickness on anti-corrosion performance of CNF-PDMS laycontact between Cu surfaces and solutions
The present work described a novel CNF-PDMS coated Cu electrodes that can be used as anodes in Microbial fuel cell (MFC) application and can be employed for different electrochemical applications in aqueous electrolytes
It was found that CNF-PDMS composites with a higher CNF percentage (8 wt%) showed the highest conductivity and best electrochemical activity

Summary

Introduction

Energy security and clean water have become major concerns in today’s world, requiring efficient technologies for renewable energy production and sustainable water treatment. Microbial fuel cell (MFC) is a promising renewable bioenergy technology using bacterial biofilms as biocatalysts to convert organic matter into electricity [1,2]. The electricity production and removal efficiency of MFCs remain low for their implementation in real-world applications [7,8]. These performance limitations are mainly due to the high cost and low-quality of materials used as anodes in MFC. The development of low cost and high-performance anode materials are still critical challenges for the practical implementation of MFCs. MFC anode materials must have good biocompatibility, high

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