Dual-Function Photothermal Wood Composites: Leveraging Graphene for Solar Conversion and Biopolymers for Sustainable Encapsulation

The development of high-performance photothermal materials from sustainable and renewable resources is crucial for advancing solar energy technologies. Herein, we present a green and sustainable strategy for fabricating a novel composite material that leverages abundant biomass and biopolymers. A cellulose-based graphene/hexadecanol composite photothermal conversion material was successfully encapsulated with fully biobased xanthan gum and wood wax oil films (denoted as WTPCM-XW). This design capitalizes on the natural hierarchical structure of delignified wood as a sustainable scaffold, effectively supporting the organic phase change material while avoiding the need for synthetic polymer matrices. The incorporation of graphene enhances photothermal conversion efficiency. Notably, the entire system is designed for minimal environmental impact, utilizing a simple aqueous process and renewable encapsulation agents. The optimal composite material WTPCM10-XW achieves an exceptional photothermal conversion efficiency of 91.6% while demonstrating outstanding dimensional stability and durability. After undergoing a 60 h static water immersion test, the material retained its original shape, exhibiting a tensile force of 928.7 N and a tensile strength of 9.3 MPa. This work provides a sustainable paradigm for designing high-performance energy storage materials from renewable resources, offering significant potential for application in energy-efficient buildings and contributing to a circular economy.