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NANO2021-Nanoteknologi og nye materiale

Bio-Sourced Alternatives for Lithium-Silicon Anodes (BALSA)

Alternative title: Alternativer for litium-silisium anoder fra biologiske kilder

Awarded: NOK 4.9 mill.

Li-ion batteries are growing in demand to support the green shift to a sustainable economy. This means that important materials can become limited in supply, meaning they are called critical raw materials. Some of these critical raw materials can come from politically unstable countries or from places using unethical labor practices. One potential solution to this problem is to develop a battery which is mostly made of materials that come from biological sources, like plants. The BALSA project aims to achieve this for several major parts of common Li-ion batteries. The Finnish project partner has processed several batches of porous silicon from barley husks using different thermal reactions. These silicons have been tested and optimized for the best battery performance. They have also been delivered to IFE for testing of the expansion, showing how pores affect the volume expansion. Early tests have also combined silicon nanoparticles with carbon nanofiber aerogel. The carbon fibers are made from plant fibers and some have been delivered to IFE for initial battery testing. Feedback has been given to improve the properties and handling of the carbon nanofiber aerogel. The BALSA battery project has also been developing new electrolytes with bio-based silica fillers, which have shown the capability to reach 5 V stability as planned in the project target. Increasing the conductivity, Li transference number, and mechanical stability through tuning the ionic liquid ratio are the next priorities. Thus, the BALSA battery can become much environmentally friendly but perform as a good, safe battery with lower cost, lower carbon footprint, and better recyclability. To know exactly how environmentally friendly the BALSA battery will be, the project will also do a life cycle analysis which looks at the carbon footprint of every step of making the BALSA battery. It will support the European Green Deal, a more circular economy, and support job creation in rural, agricultural areas by making high value materials from plants and plant waste, like barley husks.

The BALSA project aims to develop a fully bio-based Li-ion battery (LIB) anode and quasi-solid-state electrolyte, in which all the active and supporting materials are derived from biological sources, i.e., from plants. To achieve this goal, the project proposes combining mesoporous Si derived from barley husks, a cellulose-based carbon nanofiber aerogel as a free-standing support, and a bio-derived quasi-solid-state composite electrolyte containing a poly(ionic liquid) scaffold, bio-based fillers, and ionic liquid additives. The developed battery anode is combined with environmentally friendly cathode to create a lab-scale prototype, reducing the dependence of battery chemicals on the critical raw materials like Co and Cu. The developed LIB is expected to have comparable performance compared to the state-of-the-art, but with significantly lower cost and carbon footprint and the potential for recyclability. In order to properly compare and evaluate the project’s result, a holistic life cycle assessment (LCA) incorporating circular economy pathways will be conducted to benchmark the reductions in carbon footprint from the production of the BALSA battery. The performance can be contextualized by the carbon footprint, thereby meeting the goals of the European Green Deal, circular economy, and supporting skilled job creation in rural, agricultural regions. The technology at the beginning of the project is at TRL 2, as individual components have already been demonstrated in the laboratory. The target by the end of the project is TRL 4, with a lab-scale pouch cell prototype to be assembled showing some individual components of the BALSA battery to have industrial relevance. The industrial participation of Talga for anode manufacturing, testing, and materials benchmarking and of Performance Biofilaments Inc. for cellulose-based carbon nanofibre production, offer insight and perspective on commercial exploitation of the project’s results in the aftermath of the project.

Funding scheme:

NANO2021-Nanoteknologi og nye materiale