Biochar-infused cellulose foams with PEG-based phase change materials for enhanced thermal energy storage and photothermal performance
Hossein Baniasadi, Ziba Fathi, Roozbeh Abidnejad, Pedro E. S. Silva, Sanandam Bordoloi, Jaana Vapaavuori, Jukka Niskanen, Erlantz Lizundia, Eero Kontturi, Juha Lipponen
Abstract
This study presents cellulose-based foams reinforced with biochar and integrated with polyethylene glycol (PEG)-based phase change materials (PCMs) to enhance thermal energy storage and photothermal performance. The foams were fabricated using an energy-efficient, non-freeze-drying method, leveraging cellulose's inherent porosity and structural integrity to create a sustainable and scalable material platform. The optimized cellulose foams exhibited a well-balanced combination of high porosity (85 %), low density (66 kg·m −3 ), and minimal shrinkage (5 %), ensuring stability across multiple applications. The hydrophilic–hydrophobic interactions between cellulose, PEG, and biochar played a crucial role in achieving uniform PCM dispersion, enabling effective thermal energy storage (130 J·g −1 ) and temperature regulation. Durability tests confirmed the stability of phase-change properties over 100 thermal cycles, demonstrating long-term material resilience. The incorporation of biochar significantly improved photothermal efficiency (85 %) by enhancing light absorption and thermal conductivity while also reinforcing the cellulose matrix. A life cycle assessment (LCA) highlighted the environmental trade-offs, where biochar contributed to carbon sequestration, while PEG introduced a higher carbon footprint but offset other environmental burdens. This work underscores the multifunctional role of cellulose in developing sustainable, bio-based thermal management materials, providing an eco-friendly alternative to conventional insulation and energy storage systems.