Advances in nanotechnology in phase change materials and their applications

The integration of nanotechnology into phase change materials (PCMs) has substantially advanced thermal energy storage and thermoregulation technologies across diverse sectors, including building construction, electronics cooling, smart textiles, and renewable energy systems. This review provides a comprehensive and critical synthesis of recent progress in nano-enhanced phase change materials (NePCMs), focusing on how nanomaterial incorporation modifies thermophysical behavior, durability, and application performance. Various nanomaterials—such as graphene, carbon nanotubes, and metal oxides are examined for their roles in enhancing thermal conductivity, regulating phase transition kinetics, and improving overall energy efficiency. Compared with conventional PCMs, NePCMs demonstrate markedly improved performance, with reported thermal conductivity enhancements of 20–160 % at nanoparticle loadings of 0.1–5 wt.%, while maintaining latent heat reductions within an acceptable range of <10–15 %. Hybrid nanomaterials and advanced encapsulation strategies, including in-situ polymerization and silica shell encapsulation, enable 10–30 % reductions in melting and solidification times and 30–70 % suppression of supercooling, alongside enhanced leakage resistance. Long-term reliability is evidenced by > 90–95 % latent heat retention after 200–500 thermal cycles. For thermoregulation applications, system-level energy efficiency improvements of 10–25 % are reported within operating temperature windows of 20–200 °C. Despite these advances, critical challenges persist, including nanoparticle agglomeration, increased viscosity, scalability constraints, material cost escalation of 10–40 %, and unresolved environmental and health concerns. This review also evaluates emerging applications in smart textiles, electronics, temperature-controlled packaging, and solar thermal systems, highlighting the cross-sector potential of NePCMs. Furthermore, it addresses sustainability considerations, emphasizing lifecycle assessment, green synthesis, and risk mitigation strategies. Novel insights into artificial intelligence-assisted property prediction and material optimization are discussed. Overall, this work provides a quantitatively benchmarked, application-driven roadmap for the sustainable development and industrial deployment of next-generation NePCMs.