Jaana Vapaavuori: Biowaste also works with solar cells
Functional biomaterials can be used in future energy production and smart textiles. Agricultural and industrial biowaste can already be utilised in an astonishing variety of applications in laboratory conditions.
Solar cells produce clean energy, but the raw materials and manufacturing processes behind them can be environmentally harmful. For example, the cells require transparent, electrically conductive glass plates, and their production consumes a lot of energy.
Researchers at Aalto University are developing solar cells which replace the glass with a transparent, flexible film made plant biomass, such as lignocellulose. ‘Biomaterials allow for a significantly more energy efficient production process,’ says Jaana Vapaavuori, assistant professor of functional materials at the Aalto University.
Vapaavuori heads a research group focusing on multifunctional materials. By deconstructing and reassembling plant biomass, it can be turned into materials that can capture and direct light appropriately for optical applications.
Each application could require different optical properties, such as transparency, reflectiveness or UV light filtering. Bio-based solar cells, optic fibres and smart textiles utilising solar energy are examples of potential applications. Since biomaterials can easily be made flexible, they’re suitable for various use in films with high mechanical resistance and wearable electronics.
The desired functional properties are mainly achieved by modifying the components of the raw material. ‘For example, we’ve compressed the network-like structures of cellulose to a single level and produced thin films for optical applications,’ Vapaavuori says.
Profitable and sustainable
The bio-based applications are still at the basic research and prototyping stage. Scientists at Aalto University are also looking into sourcing new raw materials in a sustainable manner. Chopping down forests isn’t a sensible approach for all applications. Trees grow slowly, and there's a large market for wood in the paper, packaging and furniture industries.
According to Vapaavuori, side streams from the food industry and food processing are particularly important sources of raw materials. Last year, she and her research group manufactured a supercapacitor with fast energy storage purely from biomaterials. ‘The electrolyte came from beer brewery waste and electrodes from slaughterhouse waste,’ she says.
Using biomass in functional applications is becoming financially feasible. As waste regulations tighten, businesses have more incentives to make use of their side streams.
Biomass has the potential to replace nearly all nonrenewable raw materials. Vapaavuori is particularly inspired by the moments when an idea materialises and something new becomes possible. ‘Ideas arise from conversations with colleagues. We often toss around suggestions: maybe we could produce an edible solar cell.’
That idea hasn't materialised, yet, but it's not impossible.
Text by Terhi Hautamäki