Public defence in Bioproduct Technology, Dipl. Ing. Julian Selinger

The public defence will take place in Graz University of Technology: HS FSI 1, Inffeldgasse 11, 8010 Graz, Austria, 12:15 (UTC+2). The defence can be attended remotely at Aalto University in 240 L2, Vuorimiehentie 1, at 13:15 (UTC+3). Please arrive early as the event will start exactly on time.

Title of the thesis: The Potential of Lignocellulosic Materials for Supercapacitors and Hydrogen Storage: Activated Carbon Synthesis and Cellulose Separator Development

Thesis defender: Julian Selinger
Opponent: Prof. Agi Brandt-Talbot, Imperial College of London, United Kingdom
Custos: Prof. Michael Hummel, Aalto University School of Chemical Engineering

Energy storage devices—such as supercapacitors and hydrogen systems—are critical for renewable energy, electric vehicles, and everyday electronics. However, many of these devices still rely on fossil-based, non-degradable materials. This doctoral research explores how natural and waste-derived materials can provide a more sustainable alternative.

The study focused on using industrial side streams from coffee and sugar production, along with plant-based materials like cellulose, to create key components for energy storage devices. These materials were converted into activated carbon through high heat and chemical treatment. The resulting carbons featured extremely high surface areas—up to 3,300 m²/g—and demonstrated impressive efficiency in storing hydrogen and energy. In fact, some of the samples outperformed commercial benchmarks, doubling their performance.

Additionally, bio-based separators made from microfibrillated cellulose were developed. A crosslinking method significantly enhanced their strength and stability in wet conditions, boosting wet strength by up to 6,000%. Electrochemical tests confirmed that these cellulose-based separators performed similarly to conventional ones.

This research demonstrates that renewable and waste-derived materials can effectively replace fossil-based components in energy storage devices, without compromising performance. It paves the way for greener, circular energy technologies and shows that industrial waste can contribute to powering a cleaner future.

Keywords: Supercapacitor, Hydrogen Storage, Activated Carbon, Biomaterials, Side Streams, Paper Separator

Thesis available for public display 10 days prior to the defence at Aaltodoc.