High stable energy capsules from Nano-SiO2 recovery shell for thermal energy storage and release

Abstract image

Phase replacement materials (PCMs) store latent heat energy as they melt and release it as soon as it freezes. However, they suffer from chemical instability and thermal conductivity, which can be improved by capsulation. Here, we formatted the salt hydrate PCM (Mg (NO)3)2· 6 h2O) Pickering using an emulsion pattern inside an alcoholic nanocapsule. Analysis of the electron microscope showed a strong silicon-silicon (RSS) shell formed by an inner silicon layer about 45 nm thick, while the silicon pickling emulsifiers were laid from above. RSS nanostructured capsules are 300-1000 nm in size and have much higher thermal and chemical stability than bulk salt hydrates. The calorific value of the differential scan showed that the reduced PCM was stable during the 500+ melting / freezing cycle (equivalent to a temperature difference of 500+ day / night), with a latent temperature of 112.8 J · c.–1. Thermogravimetric analysis showed their impressive thermal stability, with a small loss of 37.2% by mass at a temperature of 800. C. Raman spectroscopy confirmed the presence of salt hydrate in RSS capsules and showed improved chemical stability than non-encrypted Mg (NO).3)2· 6 h2O. The energy capsule behavior compared to bulk material was also recorded in the macroscreen by thermal imaging, which shows that PCM melting / freezing behavior is confined to the nanocapsule core. Thermal conductivity measurement of silicon membrane by laser flash thermal conductivity method is 1.4 ± 0.2 W · (m · K)1, Which is about 7 times more than the thermal conductivity of a polymer shell (0.2 W · (m · K)1). RSS capsules containing PCMs have improved thermal stability and conductivity compared to polymer capsules and have good potential to store thermoregulation or energy.