Bioelectrochemical energy storage in a Microbial Redox Flow Cell

• Type: Article in International Scientific Journal
• Date: 2021-07-01

Authors

Márcia Santos (Author) Other; Luciana Peixoto (Author) Other; Kashif Mushtaq (Author) FEUP; Célia Dias-Ferreira (Author) Other; Adélio Mendes (Author) FEUP; Madalena Alves (Author) Other

Journal

Title: Journal of Energy Storage

Vol. 39

Initial page: 102610

Publisher: Elsevier

Scientific classification

CORDIS: Physical sciences > Chemistry

FOS: Engineering and technology > Chemical engineering

Other information

DOI: 10.1016/j.est.2021.102610

Abstract (EN): Bioelectrochemical systems (BESs) can be used to transform the electrochemical energy of fuels in electricity in Microbial Fuel Cells (MFC). However, this generated bioenergy can be captured by external loads or dissipated as heat, instead of being utilized or stored. A Microbial Redox Flow Cell (MRFC) is here presented, which demonstrates the integration of a BESs with a Redox Flow Cell (RFC); it is an innovative approach to store the energy released by the electroactive bacteria into storable electrochemical energy (electrochemical fuels) easily and efficiently convertible into electricity. The MRFC uses Geobacter sulfurreducens as biocatalyst: (i) operating as Exoelectrogenic Bacteria for the reduction of the redox pair anthraquinone-2,6-disulfonate (2,6-AQDS) in anthrahydroquinone-2,6-disulfonate (2,6-AQDSH2) (BESs as bioanode of MRFC) and (ii) operating as Electrotrophic Bacteria for oxidation of the redox pair ferrocyanide ([Fe(CN)6]4−) to ferricyanide ([Fe(CN)6]3−) (BESs as biocathode of MRFC). In the reduction of 2,6-AQDS, current density of 0.048 mA cm−2 was recorded with a bioconversion to 2,6-AQDSH2 of ca. 27%. As for the oxidation of [Fe(CN)6]4−, 35.7% was oxidized to [Fe(CN)6]3−. The bio-converted electrochemical fuels were introduced in a RFC, 2,6-AQDSH2 as negalyte and ferricyanide ([Fe(CN)6]3−) as posilyte. An MRFC, operating with 29 cycles reached Coulombic efficiencies of ca. 99% and Energy efficiencies of ca. 55%. The concept of a MRFC is successfully demonstrated.

Type (Professor's evaluation): Scientific