Graphene-enhanced biochar membrane boosts thermal storage and moisture control for ventilation systems

Researchers at Yonsei University, National University of Singapore and Dankook University have developed a paper membrane that combines food-waste-derived biochar, graphene, and a phase-change material to simultaneously store thermal energy, improve heat transfer, and manage moisture – aimed at energy-recovery ventilation and other building thermal-management systems.

Phase-change materials (PCMs) are attractive for thermal energy storage because they absorb heat as they melt and release it as they solidify, but conventional PCMs are limited by low thermal conductivity and a tendency to leak during melting. To address this, the team produced biochar from mixed food waste carbonized at 400°C, then activated it with potassium hydroxide at temperatures between 600°C and 800°C. A small amount of graphene – roughly 1% by weight – was then coated onto the biochar via ultrasonication to widen its pore structure and improve conductivity, before the resulting porous carbon was infiltrated with docosane, a paraffin-based PCM, to form the composite.

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