Carbon aerogel based composite phase change material derived from kapok fiber: Exceptional microwave absorbility and efficient solar/magnetic to thermal energy storage performance

Herein, we report a facile yet efficient strategy for fabricating a carbonized kapok fiber aerogel (CKF) based composite PCM, by incorporating magnetic guest of Fe3O4 nanoparticles and encapsulating thermal energy guest of lauric acid (LA). The obtained LA/[email protected]3O4 composite PCMs (CPM) shows an ultrahigh latent heat of 97.5% that of LA. Besides, the integration of Fe3O4 contributes to the CPM with excellent microwave absorption performance by achieving an optimal balance between the impedance matching and the high loss characteristics. The minimum reflection loss for CPM-30 is −17.3 dB at 8.4 GHz within thickness of 5.5 mm, far exceeding the practical demand of −10 dB. Furthermore, the CPM can also realize efficient solar/magnetic to thermal conversion. To the best of our knowledge, this is the first example of carbon aerogel based composite PCM prepared by facile yet renewable method that also exhibits ultrahigh thermal energy capacity, enhanced thermal conductivity, superior microwave absorption property and efficient solar/magnetic to thermal conversion performance. This study paves a way for designing of high-performance composite PCMs with numerous energy storage forms and functions by extending the reported system to other natural microtubules and functional guests.