A Systematic Review of Biopolymer Phase Change Materials for Thermal Energy Storage: Challenges, Opportunities, and Future Direction

This article systematically reviews biopolymer phase change materials (PCMs) for TES applications. The review was conducted based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using databases from Scopus, Web of Science, and Google Scholar. The biopolymer PCMs are categorized as natural, synthetic, and hybrid (a combination of natural and synthetic). A total of 82 articles were included in the analysis. Several thermal properties, mechanical properties, advancements, and challenges are discussed. This article aims to review biopolymer PCMs and identify research gaps for future development. Natural biopolymer PCMs include lipid, lignin, polysaccharides, proteins, etc. Synthetic biopolymer PCMs include supramolecular, polyethylene glycol, polyurethane, polyrotaxane, polylactic acid, etc. Hybrid biopolymer PCMs combine natural and synthetic polymers with conductive fillers, balancing high latent heat with improved thermal stability and durability, although issues, like leakage and low conductivity, persist. It is found that biopolymers can be used as the core and supporting matrix of PCMs. Several cases and configurations of core, supporting matrix, and fillers in the development of PCM from biopolymers are discussed. This article also demonstrates that several natural, synthetic, and hybrid biopolymer PCMs hold promise for demanding TES applications due to their tunable properties and reliability. Biopolymer PCMs offer a sustainable alternative to petroleum-derived substances by minimizing environmental harm, cutting carbon emissions, and promoting a circular economy. This review also highlights several challenges, such as feedstock selection, purification and encapsulation, system compatibility, and standardization, that future research might address to enable scalable, safe, and cost-effective biopolymer PCM solutions.