Phase change materials are critical to advancing thermal energy storage systems, which play an increasingly important role in grid balancing and renewable energy integration. Traditional PCMs suffer from poor thermal conductivity—typically 0.2 to 5.0 W/m·K—limiting how quickly they can charge and discharge energy. This constraint reduces overall system efficiency and makes widespread deployment impractical for many applications.
Nano-composite PCMs address these shortcomings by embedding nanoscale particles into base materials, dramatically improving thermal transport properties. Recent studies show potential improvements exceeding three orders of magnitude. However, the field lacks consensus on optimal design parameters. Significant discrepancies exist between experimental results, theoretical models, and proposed mechanisms, suggesting the science is still evolving.
A major review synthesizing over 230 studies examined organic, inorganic, eutectic, and solid-solid PCM nanocomposites. Researchers systematically evaluated how nanoparticle type, shape, concentration, manufacturing method, and processing conditions influence thermal conductivity, latent heat capacity, specific heat, and long-term stability. The analysis reveals contradictory findings in published literature and identifies underlying causes of both performance gains and eventual degradation.
Key challenges include supercooling phenomena, phase segregation, and thermal cycling stability. These issues must be resolved before nanocomposites can be deployed reliably in commercial thermal storage systems supporting variable renewable generation.
The review identifies critical research gaps and recommends priorities for advancing predictive modeling and material design. Developing standardized testing protocols and computational frameworks could accelerate commercialization. For the power sector, improved thermal storage enables better integration of solar and wind resources, reduces peak demand pressure, and improves grid resilience. Success in this area directly supports the transition to carbon-neutral electricity systems.
