Holistic insight mechanism of nano-based phase change for thermal storage applications

Nano-enhanced phase change materials (NEPCMs) have attracted much interest in thermal energy storage systems due to their higher stability, energy density, and heat transport. This study comprehensively explains the mechanisms underlying nano-based phase change enhancements. To improve the thermal conductivity of PCMs, Nanoparticles are embedded into the PCM matrix through various methods. The heat transfer resistance of PCMs during charging and discharging cycles has been improved by introducing nanoparticles in the PCM matrix. Key performance parameters, including thermal conductivity (enhanced from ∼0.2 W/m·K to >1.8 W/m·K), latent heat storage (reduction/increase of ±15-25% depending on nanoparticle type and dispersion), supercooling suppression (up to 50% improvement), and melting/freezing temperature shifts (±2-5 °C), are critically discussed. The impact of nanoparticle size (10–100 nm), concentration (0.1–10 wt%), aspect ratio, and surface functionalization is reviewed in the context of thermal reliability and stability over 100–1000 thermal cycles. Furthermore, encapsulation techniques, interfacial polymerization, and sol-gel are assessed for their contributions to mechanical reinforcement and leak prevention. The obstacles, such as nanoparticle aggregation and cost-efficiency trade-offs, are identified in this review, along with new research avenues like scalable synthesis techniques and optimizated PCM. This review discusses the latest advancements in developing nanotechnology-based PCM and their possible use in thermal energy storage.