Phase change material energy storage plays a significant role in improving energy efficiency and utilizing renewable energy. In recent years, phase change materials (PCM) for energy storage and thermal regulation in equipment and buildings have been extensively studied. However, a large proportion of PCMs are derived from fossil fuel-based industrial products such as paraffin wax, and raw PCMs face issues including leakage and limited functionality. Encapsulation materials such as expanded graphite, graphene, and microcapsules are typically employed for PCM packaging. Most of these encapsulation materials originate from petroleum derivatives, characterized by complex preparation processes, high costs, and significant pollution.
Meanwhile, biomass energy accounts for 10%–14% of global energy consumption, serving as a major global energy source and an internationally recognized zero-carbon renewable energy. Biomass materials exhibit advantages including strong adsorption capacity, abundant availability, low cost, and environmental friendliness. Leveraging the morphology-stabilizing benefits of biomass-derived activated carbon, fabricated PCMs can store more thermal energy during phase transitions, maintaining ambient temperatures within a comfortable range to achieve energy-saving and emission-reduction effects. Consequently, exploring renewable biomass-based materials and developing bio-sourced PCMs represent future trends in the industry.
Regarding material selection, bio-based porous materials-with their low cost, environmental compatibility, and broad applicability-can effectively serve as supporting materials to prepare shape-stable bio-based composite PCMs. Most supporting materials for composite PCMs are derived from petroleum derivatives, facing challenges such as complex preparation processes, high costs, and heavy pollution. Given the scarcity of fossil fuels and environmental concerns, bio-based supporting materials, owing to their biodegradability and renewability, present a viable solution and an inevitable trend. Abundant renewable bio-based materials can be sourced from plants, animals, and microorganisms. Materials based on natural bio-porous structures facilitate PCM adsorption and simplify the preparation of shape-stable composite PCMs. Fully utilizing bio-based resources aligns with green and sustainable development strategies.
Bio-based materials generally contain rich carbon sources; through carbonization and further processing, their porous structures can be reconfigured. In bio-based materials with interconnected porous architectures, cross-linked carbon networks provide thermally conductive pathways, while the porous structures offer spatial storage for PCMs. The use of bio-based materials reduces reliance on petroleum to a certain extent.
Biomass supporting materials are widely applied in porous functional material preparation due to their abundant availability, low cost, environmental friendliness, and renewability. Biomass PCMs exhibit advantages such as non-toxicity, non-corrosiveness, and excellent biocompatibility. Composite biomass PCMs demonstrate simple preparation processes, superior performance, and controllable temperature regulation. However, current research and development of biomass materials remain insufficient. Continued exploration of biomass and its derivative materials, along with novel methods for preparing porous biomass PCM is imperative.
Future Prospects:
Despite achievements in composite phase change energy storage materials-leveraging the abundant availability of biomass raw materials, superior performance of biomass-derived composite PCMs, and broad application potential-several challenges persist.
(1) Leakage during solid-liquid phase transitions: Proactive exploration of the latent properties of biomass and its derivatives is required to identify optimal composition ratios and regulate the phase transition behavior of biomass PCMs.
(2) Complex preparation processes and high costs: Innovative preparation methods for bio-based composite PCMs must be developed to streamline processes and reduce costs.
(3) Limited functionality and performance: Research should focus on tailoring biomass PCMs for diverse application scenarios, developing multifunctional variants to enhance comprehensive practicality.
