Rational Selection of Carbon Fiber Properties for High-Performance Textile Electrodes in Bioelectrochemical Systems

Liesa Pötschke,Valentina Rizzotto,Philipp Huber,Sascha Schriever,Miriam A Rosenbaum,Thomas Gries,Lars M Blank

doi:10.3389/fenrg.2019.00100

Abstract

Novel applications of bioelectrochemical systems (BES) are emerging constantly, but the majority still lacks economic viability. Especially the use of electrochemical system components without adaptation to BES requirements causes poor exploitation of the potential system performance. The electrode material is one central component that determines BES performance. While commercial carbon fiber (CF) fabrics are commonly used, their customizability as two- or three-dimensional electrode material for BES is rarely investigated. Using pure cultures of S. oneidensis MR-1, we identified CF properties impacting bacterial current generation: 1. The removal of the sizing (protective coating) is of great importance for all the fibers studied, as it acts as an electrical insulator. By desizing, the maximum current density (jmax) is increased by up to 40-fold. 2. Alteration of the filament surface chemistry results in an accelerated initial development of current generation, but the maximum current density (jmax) is hardly affected. 3. A specific yarn structure, the stretch-broken yarn, supports exceptionally high current densities. The good electrode performance is correlated to the presence of free filament ends (responsible for 41 % current increase), which are characteristic for this yarn. 4. Moreover, a combination of these free filament ends with a high degree of graphitization enhances electrode performance of a commercial fabric by 100 %. The results demonstrate that the CF selection can greatly influence the achievable electrode performance of CF fabrics, and thereby contributes to rational engineering of CF based electrodes that can be tailored for the many BES applications envisaged.

Highlights

Bioelectrochemical systems (BES) unlock novel bioeconomic technologies by utilizing the microbial ability of extracellular electron transfer to a solid electrode (Santoro et al, 2017)
This study shows that the potential of carbon fiber fabrics can be comprehensively exploited and there are several factors to be customized for the specific BES application
With the above results, we focused on identifying the relevant fiber material properties and found graphitized, stretch-broken fiber based woven fabrics to be interesting for stirred pure culture BES

Summary

Introduction

Bioelectrochemical systems (BES) unlock novel bioeconomic technologies by utilizing the microbial ability of extracellular electron transfer to a solid electrode (Santoro et al, 2017). Tailoring BES Carbon Fiber Electrodes and niche applications in which the BES has no or few competing technologies or provides an added ecological value (reviewed by Gajda et al, 2018). This can be a combined waste treatment with electricity generation in areas of low infrastructure (Ieropoulos et al, 2016; Walter et al, 2018) or avoiding costly maintenance in the case of benthic fuel cells powering remote sensors (Tender et al, 2008; Donovan et al, 2013; Ewing et al, 2017). Large scale wastewater/remediation applications (Hiegemann et al, 2016; Lu et al, 2017b; Wang et al, 2017) or high-tech applications such as the production of specialty chemicals (Raes et al, 2016; Streeck et al, 2018) are not yet ready for marketing, because here, high efficiencies are mandatory for economic operation and competitiveness with established technologies

Methods

Results

Discussion

Conclusion