Phase change material based on polypyrrole/Fe3O4- functionalized hollow kapok fiber aerogel matrix for solar /magnetic- thermal energy conversion and storage

Thermal transfer enhanced multifunctional energy conversion form-stabilized composite phase change materials (PCMs) present attractive research prospects for the energy management materials. However, complicated preparation, unsatisfied heat storage capacity and limited thermal transfer enhancement restrict their application. In this work, high-performance thermal transfer enhanced composited PCMs are facilely prepared via integration of polypyrrole/Fe3O4- functionalized hollow kapok fiber (KF) aerogel supports with paraffin wax (PW). The prepared composite PCMs achieve high thermal storage density (melting enthalpy of 161.4 J/g for the PW load mass fractions of 88%), greatly enhancement of thermal conductivity (1.06 W/m K, 307% higher than pristine PW) and outstanding cycling thermal stability. The hollow kapok fiber aerogel supports prevent the leakage and improve loading amount, and also endow the renewable and pollution-free features for the composite PCMs, which provides great potential for the commercial application on a large scale. Simultaneously, the continuous polypyrrole (PPy) dual coating and Fe3O4 nanoparticles endow the composite PCMs not only with excellent thermal conductivity, but also with solar /magnetic- thermal energy conversion characteristics which enriches the energy storage source of the materials.