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Electroless copper plating was carried out using sodium hypophosphite as red,,ucing agent for phase change microcapsules with polyurea-polyurethane shell activated by polydopamine, in order to improve the thermal conductivity of phase change microcapsules. Morphology of the microcapsules were observed by scanning electron microscope (SEM). The crystal structure and elements of the microcapsules were analyzed by X-ray diffraction (XRD) and X-ray optoelectronics spectrum (XPS). The results show that the amount of copper plating on the surface of the microcapsules increased with the increase of the concentration of the CuSO4 · 5H2O solution when the concentration of dopamine hydrochloric acid was 6 g/L. The thermal reliability of the copper plated microcapsules was demonstrated by the heating-cooling cycling test. The melting enthalpy of the Cu coated microcapsules decreased by only 4.97 J/g after 200 cycles. The thermal conductivity of the microcapsules was tested by Hot Disk thermal constant analyzer. The maximum thermal conductivity of the Cu coated microcapsules was increased by 40.14% compared with the that of the microcapsules without Cu coating, indicating that the thermal conductivity of the microcapsules was enhanced by Cu coating. The Cu coated microcapsules were applied to the thermal management of Li-ion battery. The experimental results demonstrate that the surface temperature of the Li-ion battery with high thermal conductive microcapsules for thermal management was reduced by 13.5 ℃ when the battery was charged at a rate of 2 C. [ABSTRACT FROM AUTHOR]

Mannitol and inositol, as sugar alcohol phase change materials with high latent heat, have wide application prospects in medium temperature thermal energy storage. The phase change temperature of binary sugar alcohol can be adjusted by changing the proportion of the sugar alcohol components, thus the temperature range of application is wider than that of one-component sugar alcohol. There are some problems such as leakage, oxidation and supercooling during the thermal cycles of sugar alcohols. Micro/nanoencapsulation of sugar alcohols and addition of nucleating agent are effective measures to solve the problems. In this paper, silicon carbide doped mannitol and inositol binary sugar alcohol nanocapsules were prepared. Phase change characteristics and thermal stability of the nanocapsules were studied by differential scanning calorimeter, scanning electron microscope, thermogravimetric analyzer and thermal cycling test, and the influence of silicon carbide was discussed. The results show that the nanocapsules have high phase change enthalpy, high encapsulation rate and high energy storage efficiency. The thermal decomposition temperature is higher than that of the binary sugar alcohol. The supercooling degree of the nanocapsules decreases by 32.2 ℃ compared with the binary sugar alcohol after thermal cycling. [ABSTRACT FROM AUTHOR]