Graphene’s extraordinary properties have inspired renewable energy innovations. This study demonstrates how Finnish graphite can be transformed into high-quality graphene using an eco-friendly process. The potential of graphene-based materials to replace rare metals in energy technologies is highlighted.
Teksti Sara Lund, kuvitus Dmitry Sheleva/SciGrafic, kuva Hazel Reyes
Graphene, a two-dimensional crystal made of carbon atoms, is known for its exceptional electrical, optical, and mechanical properties. However, achieving scalable production without compromising quality or sustainability remains a challenge.
Our study utilized graphite from Haapamäki, Finland, as the starting material for producing few-layer graphene (FLG). By purifying the graphite-bearing rock samples in-house to a high degree and optimizing liquid-phase exfoliation (LPE) parameters – such as temperature, surfactant concentration, and exfoliation conditions – we efficiently produced highly concentrated FLG dispersions.
”Finnish graphite transforms into graphene with eco-friendly stabilizers.”
The exfoliation process relies on aqueous, eco-friendly stabilizers, sodium cholate (SC) and cellulose nanocrystals (CNCs), eliminating the need for toxic solvents typically associated with LPE. By developing greener production methods, we reduce dependence on non-renewable or imported materials, aligning with the global push toward sustainable technologies.
From Graphene Dispersions to Functional Thin Films
FLG dispersions are highly versatile, serving as precursors for both thin films and 3D graphene-based materials. In this study, we focused on thin films, which offer high conductivity, tunable surface roughness, and compatibility with scalable deposition methods such as spray-coating, making them ideal for applications in energy devices and biosensors.
The spray-coated graphene thin films exhibited high electrical conductivity (a key attribute for energy applications), efficient electron transfer, and nanoscale surface roughness. While the LPE process reduces the lateral size of graphene sheets, this feature can be advantageous for applications such as biosensors, flexible electronics, and energy storage devices, where smaller flakes enhance surface interactions and improve performance.
Towards Sustainable Energy Solutions and Application in Biophotovoltaics
Graphene’s inherent properties, including high conductivity and mechanical strength, make it a promising material for sustainable energy technologies. Additionally, FLG production can be scaled efficiently, further enhancing its potential for use in solar cells, supercapacitors, and fuel cells.
Furthermore, our research also explored the biocompatibility of these graphene-based materials, particularly their compatibility with photosynthetic microorganisms. This property enables bio-integrated applications in renewable energy technologies, such as biophotovoltaics (BPVs).
In BPVs, sunlight is converted into electricity using microorganisms like cyanobacteria, which use water as the source of electrons. The graphene-based thin films served as anode materials, harvesting electrons from the cells during biophotoelectrochemical water splitting.
The nanoscale roughness of the graphene-based films supports the formation of robust and healthy biofilms on the electrode surface, and the hydrophilic nature of the films promotes efficient electron transfer. Electrochemical assessments revealed that the graphene-based electrodes not only facilitated efficient electron transfer but were also stable in aqueous environments, maintaining their performance over time.
BPV experiments demonstrated the ability of the graphene-based films to harvest photogenerated charges from cyanobacteria under illumination, achieving performance comparable to or exceeding that of traditional indium tin oxide (ITO) electrodes in similar conditions.
Paving the Way for Metal Substitution
Since indium is rare and expensive, graphene-based materials—derived from abundant carbon sources and stabilized with cellulose nanocrystals, the most abundant biopolymer—offer a more sustainable alternative. The CNC component also enhances electrode stability and robustness, supporting long-term applications in renewable energy technologies.
”Graphene-based material offer a sustainable alternative to rare metals like indium.”
By covering the entire value chain – from raw Finnish graphite to applications – this work underscores the potential of graphene-based materials to replace rare and costly metals like indium in advanced technologies. Derived from abundant carbon sources and stabilized with cellulose nanocrystals, a renewable biopolymer, these materials not only provide a sustainable alternative but also enhance electrode stability and robustness, supporting long-term applications in renewable energy technologies.
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Sara Lund
Sara Lund recently completed her PhD in the Analytical and Physical Chemistry groups at the Laboratory of Molecular Science and Engineering, Åbo Akademi University. Her doctoral research focused on developing graphene-based electrode materials from natural flake graphite, with expertise in material characterization. The application of the electrode materials in biophotovoltaics was carried out in collaboration with the PhotoMicrobes group at the Department of Life Technologies, University of Turku.
Sara Lund
Recently completed her PhD in the Analytical and Physical Chemistry groups at the Laboratory of Molecular Science and Engineering, Åbo Akademi University. Her doctoral research focused on developing graphene-based electrode materials from natural flake graphite, with expertise in material characterization. The application of the electrode materials in biophotovoltaics was carried out in collaboration with the PhotoMicrobes group at the Department of Life Technologies, University of Turku.
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