Eco-friendly shape-stabilized phase change materials: Improving thermal performance, reducing pollution, and enabling sustainable energy solutions.

Phase change materials store and release large amounts of latent heat, yet leakage on melting and low thermal conductivity limit their use in thermal energy storage. Confining them in porous supports prevents leakage, but many conventional supports carry high cost and environmental burden. This review synthesizes how biomass-derived porous supports offer a sustainable alternative. It compares three carbonization routes, direct pyrolysis, hydrothermal carbonization, and activation-enabled carbonization, across pore development, PCM loading, leakage resistance, cost, and environmental impact, and examines hybridization with graphene, expanded graphite, metals, and ceramics to raise thermal conductivity. The evidence shows that filler topology and interfacial design govern performance more than filler identity. These insights map a practical, lower-impact route toward scalable bio-based thermal storage for buildings, textiles, desalination, and solar applications.