Sustainable thermal energy storage system based on green-delignified corn husk-phase change composite

The growing demand for thermal energy and dependence on fossil fuels highlight the need for efficient and sustainable thermal energy storage (TES) systems. In this study, raw corn husk (RCH) was converted into a porous delignified corn husk (DCH) substrate via a green treatment, providing a suitable scaffold for phase change material integration. Polyethylene glycol (PEG₁₀₀₀) was successfully impregnated into the DCH through vacuum infiltration at 70 °C, forming a shape-stable composite (DCH-PCM). To enhance energy storage performance, the composite surface was coated with a carbon nanotubes/cellulose nanofibers (CNTs-CNFs) layer, thereby improving solar absorption and preventing leakage during phase transitions. The resulting DCH-PCM exhibited high solar absorbance (95%), a latent heat of 95.6 J g⁻¹, and excellent thermal reliability, enabling efficient absorption, storage, and release of thermal energy. These characteristics demonstrate the strong potential of the developed composite for solar-driven TES applications, particularly in thermal management and energy-saving systems. Additionally, this work offers a sustainable approach for converting agricultural waste into high-performance energy storage materials, supporting renewable energy utilization and environmental sustainability.