Integrated benchmarking of nano‐enhanced phase change materials for thermal energy storage: Material performance, system integration, AI optimization, techno‐economic assessment, and sustainability challenges

Abstract Thermal energy storage (TES) supports renewable energy integration and waste‐heat recovery, but conventional phase change materials (PCMs) suffer from low thermal conductivity, slow response, leakage, segregation, and limited stability. To address these limitations, this review evaluates nano‐enhanced PCMs (NePCMs) for advanced heat storage by analyzing material performance, system applications, artificial intelligence (AI)‐assisted optimization, techno‐economic feasibility, and environmental impacts. A systematic review of 136 studies was conducted covering nano‐additive effects, AI‐based prediction methods, cost analysis, and lifecycle considerations. Results show nano‐additives can improve PCM thermal conductivity by 30%–120% and enhance charging/discharging rates by 30%–60%; however, these gains may reduce latent heat by 2%–10% and increase viscosity, sedimentation risk, and material cost. Carbon‐based additives provide the highest conductivity enhancement, while metal oxides offer better chemical stability and lower cost. Consequently, NePCM‐TES systems show strong potential for concentrated solar power, HVAC, buildings, and industrial waste‐heat recovery, with reported Levelized Cost of Heat (LCOH) values of 0.04–0.12 USD kWh th −1 under favorable operating conditions. Further, AI models improve property prediction and design optimization, but their reliability is limited by small datasets, overfitting, and weak transferability across PCM classes. Despite these advances, major challenges remain long‐term cycling degradation, nanoparticle sedimentation, leakage, encapsulation failure, lack of standardized testing, and insufficient pilot‐scale validation. This review provides a benchmarked material–system–AI–economics framework for evaluating the potential of NePCM deployment beyond conventional TES technologies.