Fabrication of Cellulose-Graphite Foam via Ion Cross-linking and Ambient-Drying

Conventional plastic foams are usually produced by fossil-fuel-derived polymers, which are difficult to degrade in nature. As an alternative, cellulose is a promising biodegradable polymer that can be used to fabricate greener foams, yet such a process typically relies on methods (e.g., freeze-drying and supercritical-drying) that are hardly scalable and time-consuming. Here, we develop a fast and scalable approach to prepare cellulose-graphite foams via rapidly cross-linking the cellulose fibrils in metal ions-containing solution followed by ambient drying. The prepared foams exhibit low density, high compressive strength, and excellent water stability. Moreover, the cross-linking of the cellulose fibrils can be triggered by various metal ions, indicating good universality. We further use density functional theory to reveal the cross-linking effect of different ions, which shows good agreement with our experimental observation. Our approach presents a sustainable route toward low-cost, environmentally friendly, and scalable foam production for a range of applications.

Automated summary

Conventional plastic foams made from fossil-fuel-derived polymers are difficult to biodegrade in nature. This study presents a fast and scalable method to prepare cellulose-graphite foams by cross-linking cellulose fibrils in a metal ions-containing solution, followed by ambient drying. The resulting foams exhibit low density, high compressive strength, and excellent water stability. The cross-linking effect of different metal ions is revealed through density functional theory, showing good agreement with experimental observations. This approach offers a sustainable route for low-cost, environmentally friendly, and scalable foam production for various applications.