Chemically Modified Wood Captures Sunlight and Stores It as Heat

Key Takeaways

• Delignified balsa wood coated with black phosphorene, metal‑polyphenol, silver, alkyl layers.
• Composite stores 175 kJ kg⁻¹ latent heat with 91.27 % photothermal efficiency.
• Achieves fire self‑extinguishment in 120 s, reducing heat release by ~30 %.
• Silver nanoparticles give antibacterial activity against E. coli and S. aureus.
• Maintains 0.65 V output on thermoelectric generator for minutes after sunset.

Pulse Analysis

The new wood‑based composite leverages the natural micro‑channel architecture of delignified balsa to host a fatty‑acid phase‑change material, dramatically increasing energy density while keeping the structure lightweight. By sequentially grafting black phosphorene, a metal‑polyphenol protective layer, silver nanoparticles and long‑chain alkyl groups, the researchers created a single‑volume system that simultaneously absorbs sunlight, stores heat, repels water, resists flame and inhibits microbes. This integrated design sidesteps the trade‑offs that have plagued previous attempts using separate additives or high‑temperature carbonization, preserving the wood’s porosity and chemical reactivity.

Performance testing under one‑sun illumination shows a photothermal conversion and storage efficiency exceeding 91 %, with a latent heat capacity of roughly 175 kJ per kilogram of composite. When the light source is removed, the stearic‑acid PCM solidifies, releasing stored heat and sustaining a temperature gradient that powers a thermoelectric generator at about 0.65 V for several minutes—enough to run low‑power devices such as a small fan. The composite also demonstrates robust fire safety, self‑extinguishing within two minutes and cutting peak heat release by more than a quarter, while silver‑nanoparticle‑induced antibacterial action protects against common pathogens that could degrade bio‑derived materials.

Beyond the immediate laboratory results, the modular interfacial‑engineering strategy offers a scalable pathway for renewable‑energy hardware. The chemistry can be adapted to other two‑dimensional nanomaterials and diverse biomass scaffolds, potentially enabling cost‑effective solar‑thermal collectors, off‑grid power modules, and resilient building materials. As the energy sector seeks storage solutions that combine high efficiency, durability and environmental friendliness, this wood‑derived composite positions itself as a compelling candidate for next‑generation sustainable power systems.