title: Continuous Carbon Nanotube-Ultrathin Graphite Hybrid Foams for Increased Thermal Conductivity and Suppressed Subcooling in Composite Phase Change Materials.
abstract: Continuous ultrathin graphite foams (UGFs) have been actively researched recently to obtain composite materials with increased thermal conductivities. However, the large pore size of these graphitic foams has resulted in large thermal resistance values for heat conduction from inside the pore to the high thermal conductivity graphitic struts. Here, we demonstrate that the effective thermal conductivity of these UGF composites can be increased further by growing long CNT networks directly from the graphite struts of UGFs into the pore space. When erythritol, a phase change material for thermal energy storage, is used to fill the pores of UGF-CNT hybrids, the thermal conductivity of the UGF-CNT/erythritol composite was found to increase by as much as a factor of 1.8 compared to that of a UGF/erythritol composite, whereas breaking the UGF-CNT bonding in the hybrid composite resulted in a drop in the effective room-temperature thermal conductivity from about 4.1 ± 0.3 W m(-1) K(-1) to about 2.9 ± 0.2 W m(-1) K(-1) for the same UGF and CNT loadings of about 1.8 and 0.8 wt %, respectively. Moreover, we discovered that the hybrid structure strongly suppresses subcooling of erythritol due to the heterogeneous nucleation of erythritol at interfaces with the graphitic structures.
authors.affiliation: Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin , Austin, Texas 78712, United States.|CNR-INO, Sensor Lab, The University of Brescia , Via Branze 45, 25123, Brescia, Italy.
authors.forename: Iskandar
authors.initials: I
authors.lastname: Kholmanov
authors.affiliation: Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Jaehyun
authors.initials: J
authors.lastname: Kim
authors.affiliation: Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Eric
authors.initials: E
authors.lastname: Ou
authors.affiliation: Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS) , Ulsan 689-798, Republic of Korea.|Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798, Republic of Korea.
authors.forename: Rodney S
authors.initials: RS
authors.lastname: Ruoff
authors.affiliation: Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Li
authors.initials: L
authors.lastname: Shi
keywords: carbon nanotubes; composites; phase change materials; thermal conductivity; ultrathin graphite foam