Ultralight three-dimensional, carbon-based nanocomposites for thermal energy storage

Polymer based nanocomposites consisting of elastic three-dimensional (3D) carbon foam (CF), paraffin wax and graphene nanoplatelets (GNPs) have been created and evaluated for thermal energy storage. The ultralight, highly porous (∼98.6% porosity), and flexible CFs with densities of 2.84–5.26 mg/cm3 have been used as the backbone skeleton to accommodate phase change wax and nanoscale thermal conductive enhancer, GNP. Low level of defects and the ordered sp2 configuration allow the resulting CFs to exhibit excellent cyclic compressive behavior at strains up to 95%, while retaining part of their elastic properties even after 100 cycles of testing. By dispersing the highly conductive GNP nanofillers in paraffin wax and infiltrating them into the flexible CFs, the resultant nanocomposites were observed to possess enhanced overall thermal conductivity up to 0.76 W/(m K), representing an impressive improvement of 226%, which is highly desirable for thermal engineering.