A photothermal conversion phase change composite material with energy storage and long-term heat release based on banana nanocellulose/montmorillonite aerogel

In this study, banana nanocellulose/montmorillonite aerogel acts as support material and by vacuum impregnation paraffin conducts as latent heat storage material to prepare a shape-stabilized phase change composite. The microstructure, functional groups, and crystallinity of the samples were determined by SEM, FTIR, and XRD. The thermal storage and thermal cycling properties of the samples were measured by DSC, and the thermal conductivity was measured by thermal constant analyzer. The ΔH m /ΔH c values of CMP are 93.9–96.3 % and 91.9–97.4 % of paraffin. There is no obvious leakage of the composite after heated at 80 °C for 1 h. The temperature of the composite can reach 83.5 °C under an intensity of 150 mW/cm 2 simulated sunlight and the heat release time without sunlight can reach 8 h. The composites prepared have excellent shape stability, thermal conductivity, and photothermal conversion efficiency, which can achieve efficient thermal energy storage and long-term thermal energy release. At the same time, this work provides reference value for the resource utilization of banana wasted stem. • Cellulose extracted from banana stems can bring practical and economic value. • Composites have low leakage rate and high loading rate. • It can still release heat for a long time without sunlight exposure.