Synthesis and optimization of GO/TiO2@n-octadecane microcapsules for thermal management of smartphone charging

•Stirring rate, pH, and droplet-adding rate in the preparation of MPCMs are optimized.•The MPCMs modified by GO have excellent thermal stability and fire resistance.•Optimal MPCMs can effectively reduce peak temperature of smartphone charging.•MPCMs with 1 wt% GO balance the enthalpy of phase change and thermal conductivity. To reduce the charging temperature of smartphones effectively, the GO/TiO2@n-octadecane microcapsules were prepared in this study. Various testing methods were used to analyze the thermal performance of microcapsules. To achieve maximum enthalpy of phase change, various preparation conditions for the preparation process were optimized. The GO was doped into the optimized microencapsulated phase change materials for further analysis. Moreover, the GO/TiO2@n-octadecane microcapsules were used for the thermal management of smartphone charging. GO was attached to the surface of microcapsules, enhancing the thermal conductivity. Microcapsules were physically encapsulated without any chemical reactions. The enthalpies of microcapsules decreased with the proportion of GO, while the thermal conductivity increased. The prepared GO/TiO2@n-octadecane microcapsules had excellent thermal cycling stability and fire resistance. The GO could reduce the mass loss of microcapsules in high temperatures. Microencapsulated phase change materials containing 0 wt%, 1 wt%, 2 wt%, and 3 wt% GO had an excellent ability to reduce the charging temperature of smartphones, which could reduce the peak charging temperature of smartphones by 2.9, 3.1, 2.7, and 2.5 ℃, respectively. Microcapsules containing 1 wt% GO had a large enthalpy of phase transition and high thermal conductivity, which could most effectively reduce the peak charging temperature of the smartphone. Therefore, microcapsules with 1 wt% GO were the optimal microcapsules for the thermal management of smartphone charging.