Montmorillonite aerogel-based phase change composites with efficient thermal energy storage

Thermal storage with phase change materials holds broad application prospects in the fields of solar energy utilization and thermal management. The development of thermal storage materials with high thermal storage capacity and fast energy storage/release rate remains a critical challenge. Herein, montmorillonite aerogel was prepared by a simple hydrothermal and freeze-drying method, and then stearic acid was fused and impregnated into composite aerogel to obtain form-stable phase change composites. The ultrahigh porosity of montmorillonite aerogel endows the phase-change composite material with a high thermal storage capacity of 177.9 J/g. Meanwhile, the combination of carbon and montmorillonite can increase the thermal storage capacity of the phase change composite material to as high as 197.4 J/g, with a latent heat retention rate of 97.4 %. The thermal conductivity of montmorillonite‑carbon aerogel is up to 0.4075 W·m⁻¹ K⁻¹, which is attributed to three-dimensional connectivity network structure of aerogel and high thermal conductivity of the carbon material. Furthermore, phase change composites possess excellent cycling stability of energy storage/release due to robust structure of montmorillonite aerogel. This work provides valuable guidance for the advancement of clay aerogel based composite phase change thermal storage materials.