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Investigation and development of power-generating building material systems based on air-cathode microbial fuel cell using Geobacter sulfurreducens

Zhang, Shifan (2023)
Investigation and development of power-generating building material systems based on air-cathode microbial fuel cell using Geobacter sulfurreducens.
Technische Universität Darmstadt
doi: 10.26083/tuprints-00024516
Ph.D. Thesis, Primary publication, Publisher's Version

Abstract

The increasing environmental pollution, carbon emissions, and limited fossil fuel reserves necessitate the gradual replacement of fossil fuels with sustainable and renewable green energy sources. However, current green energy sources have specific requirements for their application, such as solar energy requiring sufficient sunlight and wind energy requiring sufficient wind without negative impacts on the environment. Hydrogen fuel cells are also gradually being utilized as a clean energy source. As a means of power generation, the key factor in fuel cells is the catalytic effect on the reaction. In nature, there exists a group of electrochemically active microorganisms that are widely distributed in soil and wastewater. They act as natural catalysts in fuel cells. Although these microbial fuel cells have seen significant improvements in power generation in recent years, their application has not been widely promoted due to cost.

Concrete is the most widely used building material in the world. Its low raw material cost, high compressive strength, and simple production process make it an attractive and easily applicable material in the field of construction and building. If mineral materials can be used to make fuel cells, the manufacturing cost would be greatly reduced, which would greatly benefit the development of fuel cells.

In order to use mineral materials as electrodes for fuel cells, they must have a low enough electrical resistance. This PhD research is based on the theory of percolation and studies two types of building materials, Portland cement and geopolymer, from a microstructural perspective. By comparing their differences in microstructure and the changes in electrical conductivity of their mixes in dry and wet conditions, it is found that when the volume fraction of conductive fillers exceeds its percolation threshold, the overall electrical conductivity of the composite is no longer related to its water content. In other words, the conductive mechanism in the mix is mainly in the form of electronic conduction, and the ionic conduction in the solution has little impact on the electrical conductivity of the mix. The geopolymer, due to their excellent microstructure, make it possible for direct electronic transitions of conductive fillers. Therefore, graphite-geopolymer composite have better electronic conductivity than graphite-portland cement composite at the same graphite content.

To study the conductive mechanism of geopolymer and graphite mixture more in-depth, a Monte Carlo method was employed to simulate the percolation threshold of the mixture. The model, based on the HYMOSTRUC3D framework, is a three-dimensional model that considers the particle size distribution, and it can accurately describe the spatial distribution and interactions of different particles. By introducing the concept of effective volume fraction, the influence of pores on the mixture was eliminated. The effective medium model simulated the relationship between the overall electrical conductivity and graphite effective volume fraction, which was consistent with experimental data.

The microstructural properties of geopolymers make it possible to create high-performance electrical conductive materials using low-cost graphite particles. The porous structure of this mixture also provides necessary growth space for microorganisms, leading to the formation of more biofilm. In order to verify the feasibility of this mineral-based electrode as a microbial fuel cell, a single-strain Geobacter sulfurreducens culture was used to cultivate a dual-chamber microbial fuel cell. During the one-week testing period, the microbial fuel cell with the graphite geopolymer anode had a peak operating current density of 155.9 A·s/cm² even higher than the operating current density of 144.5 A·s/cm² with graphite as the electrode.

This research also explored the feasibility of large-scale application of microbial fuel cells using the mineral-based electrode. The study found that the mineral-based electrode can be used to power a green LED light, and by connecting 224 soil-based microbial fuel cells in series and parallel, and creating a control board for energy collection, it was possible to power a lighting system in a bike shed. The Ph.D. thesis demonstrates the feasibility of using mineral-based materials as electrodes in microbial fuel cells and explains the conductive mechanism in the composite. Due to its superior electrical conductivity, the mineral-based material can also be used in other types of fuel cells and even rechargeable batteries.

Item Type: Ph.D. Thesis
Erschienen: 2023
Creators: Zhang, Shifan
Type of entry: Primary publication
Title: Investigation and development of power-generating building material systems based on air-cathode microbial fuel cell using Geobacter sulfurreducens
Language: English
Referees: Koenders, Prof. Dr. Eduardus ; Lackner, Prof. Dr. Susanne
Date: 2 November 2023
Place of Publication: Darmstadt
Collation: XIV, 114, A-24 Seiten
Refereed: 22 June 2023
DOI: 10.26083/tuprints-00024516
URL / URN: https://tuprints.ulb.tu-darmstadt.de/24516
Abstract:

The increasing environmental pollution, carbon emissions, and limited fossil fuel reserves necessitate the gradual replacement of fossil fuels with sustainable and renewable green energy sources. However, current green energy sources have specific requirements for their application, such as solar energy requiring sufficient sunlight and wind energy requiring sufficient wind without negative impacts on the environment. Hydrogen fuel cells are also gradually being utilized as a clean energy source. As a means of power generation, the key factor in fuel cells is the catalytic effect on the reaction. In nature, there exists a group of electrochemically active microorganisms that are widely distributed in soil and wastewater. They act as natural catalysts in fuel cells. Although these microbial fuel cells have seen significant improvements in power generation in recent years, their application has not been widely promoted due to cost.

Concrete is the most widely used building material in the world. Its low raw material cost, high compressive strength, and simple production process make it an attractive and easily applicable material in the field of construction and building. If mineral materials can be used to make fuel cells, the manufacturing cost would be greatly reduced, which would greatly benefit the development of fuel cells.

In order to use mineral materials as electrodes for fuel cells, they must have a low enough electrical resistance. This PhD research is based on the theory of percolation and studies two types of building materials, Portland cement and geopolymer, from a microstructural perspective. By comparing their differences in microstructure and the changes in electrical conductivity of their mixes in dry and wet conditions, it is found that when the volume fraction of conductive fillers exceeds its percolation threshold, the overall electrical conductivity of the composite is no longer related to its water content. In other words, the conductive mechanism in the mix is mainly in the form of electronic conduction, and the ionic conduction in the solution has little impact on the electrical conductivity of the mix. The geopolymer, due to their excellent microstructure, make it possible for direct electronic transitions of conductive fillers. Therefore, graphite-geopolymer composite have better electronic conductivity than graphite-portland cement composite at the same graphite content.

To study the conductive mechanism of geopolymer and graphite mixture more in-depth, a Monte Carlo method was employed to simulate the percolation threshold of the mixture. The model, based on the HYMOSTRUC3D framework, is a three-dimensional model that considers the particle size distribution, and it can accurately describe the spatial distribution and interactions of different particles. By introducing the concept of effective volume fraction, the influence of pores on the mixture was eliminated. The effective medium model simulated the relationship between the overall electrical conductivity and graphite effective volume fraction, which was consistent with experimental data.

The microstructural properties of geopolymers make it possible to create high-performance electrical conductive materials using low-cost graphite particles. The porous structure of this mixture also provides necessary growth space for microorganisms, leading to the formation of more biofilm. In order to verify the feasibility of this mineral-based electrode as a microbial fuel cell, a single-strain Geobacter sulfurreducens culture was used to cultivate a dual-chamber microbial fuel cell. During the one-week testing period, the microbial fuel cell with the graphite geopolymer anode had a peak operating current density of 155.9 A·s/cm² even higher than the operating current density of 144.5 A·s/cm² with graphite as the electrode.

This research also explored the feasibility of large-scale application of microbial fuel cells using the mineral-based electrode. The study found that the mineral-based electrode can be used to power a green LED light, and by connecting 224 soil-based microbial fuel cells in series and parallel, and creating a control board for energy collection, it was possible to power a lighting system in a bike shed. The Ph.D. thesis demonstrates the feasibility of using mineral-based materials as electrodes in microbial fuel cells and explains the conductive mechanism in the composite. Due to its superior electrical conductivity, the mineral-based material can also be used in other types of fuel cells and even rechargeable batteries.

Alternative Abstract:
Alternative abstract Language

Die zunehmende Umweltverschmutzung, der Ausstoß von Kohlendioxid und die begrenzten fossilen Brennstoffreserven machen die schrittweise Ersetzung von fossilen Brennstoffen durch nachhaltige und erneuerbare grüne Energiequellen erforderlich. Allerdings haben aktuelle grüne Energiequellen spezifische Anforderungen für ihre Anwendung, wie etwa die ausreichende Sonneneinstrahlung für Solarenergie und ausreichend Wind für Windenergie, ohne negative Auswirkungen auf die Umwelt. Wasserstoffbrennstoffzellen werden ebenfalls allmählich als saubere Energiequelle genutzt. Als Methode zur Stromerzeugung liegt der Schlüssel in Brennstoffzellen in der katalytischen Wirkung auf die Reaktion. In der Natur existiert eine Gruppe von elektrochemisch aktiven Mikroorganismen, die weit verbreitet im Boden und Abwasser vorkommen. Sie wirken als natürliche Katalysatoren in Brennstoffzellen. Obwohl diese mikrobiellen Brennstoffzellen in den letzten Jahren erhebliche Fortschritte bei der Stromerzeugung gemacht haben, wurde ihre Anwendung aufgrund der Kosten nicht weit verbreitet gefördert.

Beton ist das weltweit am häufigsten verwendete Baumaterial. Sein geringer Rohstoffkosten, hohe Druckfestigkeit und einfacher Herstellungsprozess machen es zu einem attraktiven und leicht anwendbaren Material im Bereich Bauwesen. Wenn mineralische Materialien zur Herstellung von Brennstoffzellen verwendet werden können, würde dies die Herstellungskosten erheblich senken und die Entwicklung von Brennstoffzellen erheblich fördern.

Um mineralische Materialien als Elektroden für Brennstoffzellen verwenden zu können, müssen sie einen niedrigen elektrischen Widerstand aufweisen. Diese Doktorarbeit basiert auf der Theorie der Perkolation und untersucht zwei Arten von Baumaterialien, Portlandzement und Geopolymer, aus mikrostruktureller Perspektive. Durch den Vergleich ihrer Unterschiede in der Mikrostruktur und der Änderungen der elektrischen Leitfähigkeit ihrer Mischungen unter trockenen und feuchten Bedingungen wurde festgestellt, dass, wenn der Volumenanteil leitfähiger Füllstoffe seinen Perkolationsschwellenwert überschreitet, die Gesamtelektrische Leitfähigkeit des Verbundmaterials nicht mehr von seinem Wassergehalt abhängt. Mit anderen Worten, der leitfähige Mechanismus in der Mischung erfolgt hauptsächlich in Form von elektronischer Leitung, und die ionische Leitung in der Lösung hat wenig Einfluss auf die elektrische Leitfähigkeit der Mischung. Das Geopolymer ermöglicht aufgrund seiner ausgezeichneten Mikrostruktur direkte elektronische Übergänge leitfähiger Füllstoffe. Daher weisen Graphit-Geopolymer-Verbundstoffe bei gleichem Graphitgehalt eine bessere elektronische Leitfähigkeit als Graphit-Portlandzement-Verbundstoffe auf.

Um den leitfähigen Mechanismus von Geopolymer und Graphitmischung genauer zu untersuchen, wurde die Monte-Carlo-Methode verwendet, um den Perkolationsschwellenwert der Mischung zu simulieren. Das Modell, basierend auf dem HYMOSTRUC3D-Framework, ist ein dreidimensionales Modell, das die Partikelgrößenverteilung berücksichtigt und die räumliche Verteilung und Interaktionen verschiedener Partikel genau beschreiben kann. Durch die Einführung des Konzepts des effektiven Volumenanteils wurde der Einfluss von Poren auf die Mischung eliminiert. Das effektive Mediumsmodell simuliert die Beziehung zwischen der Gesamtelektrischen Leitfähigkeit und dem effektiven Volumenanteil von Graphit, was mit den experimentellen Daten übereinstimmt.

Die mikrostrukturellen Eigenschaften von Geopolymeren ermöglichen es, hochleistungsfähige elektrisch leitfähige Materialien unter Verwendung kostengünstiger Graphitpartikel herzustellen. Die poröse Struktur dieser Mischung bietet auch notwendigen Raum für das Wachstum von Mikroorganismen, was zur Bildung von mehr Biofilm führt. Um die Machbarkeit dieser mineralbasierten Elektrode als Mikrobielle Brennstoffzelle zu überprüfen, wurde eine Einzelstammkultur von Geobacter sulfurreducens verwendet, um eine Zweikammer-Mikrobielle Brennstoffzelle zu züchten. Während der einwöchigen Testphase hatte die Mikrobielle Brennstoffzelle mit der Graphit-Geopolymer-Anode eine Spitzenbetriebsstromdichte von 155,9 A·s/cm², sogar höher als die Betriebsstromdichte von 144,5 A·s/cm² mit Graphit als Elektrode.

Diese Forschung untersuchte auch die Machbarkeit der groß angelegten Anwendung von Mikrobiellen Brennstoffzellen unter Verwendung der mineralbasierten Elektrode. Die Studie ergab, dass die mineralbasierte Elektrode verwendet werden kann, um eine grüne LED-Leuchte mit Strom zu versorgen. Durch das Verbinden von 224 bodenbasierten Mikrobiellen Brennstoffzellen in Serie und Parallel und die Erstellung einer Steuerplatine zur Energieerfassung war es möglich, ein Beleuchtungssystem in einem Fahrradschuppen mit Strom zu versorgen. Die Doktorarbeit zeigt die Machbarkeit der Verwendung von mineralbasierten Materialien als Elektroden in Mikrobiellen Brennstoffzellen auf und erläutert den leitfähigen Mechanismus im Verbundmaterial. Aufgrund seiner hervorragenden elektrischen Leitfähigkeit kann das mineralbasierte Material auch in anderen Arten von Brennstoffzellen und sogar wiederaufladbaren Batterien verwendet werden.

German
Status: Publisher's Version
URN: urn:nbn:de:tuda-tuprints-245167
Classification DDC: 500 Science and mathematics > 570 Life sciences, biology
600 Technology, medicine, applied sciences > 620 Engineering and machine engineering
600 Technology, medicine, applied sciences > 624 Civil engineering and environmental protection engineering
Divisions: 13 Department of Civil and Environmental Engineering Sciences
13 Department of Civil and Environmental Engineering Sciences > Institute of Construction and Building Materials
13 Department of Civil and Environmental Engineering Sciences > Institute of Construction and Building Materials > Beton- und Materialentwicklung
13 Department of Civil and Environmental Engineering Sciences > Institute of Construction and Building Materials > Technologieentwicklung
TU-Projects: Bund/BBR/BBSR|SWD-10.08.18.7-18.25|Innovative Anode f.
Date Deposited: 02 Nov 2023 14:51
Last Modified: 03 Nov 2023 10:33
PPN:
Referees: Koenders, Prof. Dr. Eduardus ; Lackner, Prof. Dr. Susanne
Refereed / Verteidigung / mdl. Prüfung: 22 June 2023
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