Optimization of n-Eicosane as Core Material for Microencapsulation in Silica Shell for Enhanced Thermal Energy Storage Performance

초록

Silica-encapsulated n-eicosane nanophase change materials(EISI NPCMs) are synthesized via a single-step sol‒gel process to enhance the stability and performance of latent heat thermal energy storage(LHTES) systems. The effects of core-to-shell ratio(EISI-1, EISI-2, and EISI-3) on morphology, particle size, thermal behavior, and encapsulation efficiency are systematically investigated. FTIR spectra confirm physical encapsulation without chemical modification, preserving the intrinsic molecular structure of both core and shell materials. SEM analysis reveals that EISI-2 exhibits the smallest mean particle size(~250nm) and the most uniform morphology, indicating optimal shell formation. DSC analysis shows that all composites retain the melting and crystallization transitions of pure n-eicosane, with slight temperature shifts due to confinement effects. Latent heat values decrease after encapsulation, reflecting the inert nature of the silica shell; however, EISI-2 achieves the highest melting enthalpy(127.6J/g), encapsulation ratio(51.29%), and encapsulation efficiency(51.86%). The optimized morphology and higher surface area of EISI-2 improve heat transfer potential and thermal cycling stability. This study demonstrates that controlling the core-to-shell ratio enables the design of silica-encapsulated PCMs with superior thermal storage capacity, stability, and leakage resistance, offering significant potential for applications in building climate control, solar thermal systems, and electronic cooling.

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