Speaker
Description
Interconnected pore graphite foams have proven to be excellent materials for thermal management applications due to their superior property combination. Traditionally, the most successful foaming methods, which involve blowing graphite precursors such as mesophase pitch, have a number of drawbacks: there is no perfect control over the volume fraction of pores generated, and control of the shape and distribution of pores is difficult. In addition, the graphitization process incurs significant costs in the fabrication of these materials. Therefore, novel and more cost-effective methods to control the porous structure of these materials are needed. Recent research has shown that graphite foams can be produced by combining graphite particulate material with blowing agents and binders. Although these foams are inexpensive to produce, they have extremely low thermal conductivities (0.5-4.5 W/(m-K) for pore volume fractions between 0.4 and 0.7).1
In this work, the authors propose the design, fabrication and characterization of a novel class of interconnected pore graphite/carbon foams with excellent thermal conductivity using natural graphite flakes. The novel materials were synthesized in three steps: (i) preparation of self-supporting preforms from a homogeneous mixture of aligned graphite flakes (GF), sodium chloride (NaCl - template) and sucrose particles (S - binder), (ii) caramelization and carbonization of the sucrose and (iii) dissolution of the NaCl. Different GF:NaCl:S combinations were investigated and foams with pore volume fraction ranging from 0.20 to 0.85 were obtained. While the carbonised sucrose contributes to the dimensional stability of the material, it is the flake-flake contacts that provide adequate thermal conductivity. The materials produced exhibit thermal conductivities of up to 174 W/(m-K), which is more than 20 times the thermal conductivity of graphite flakes forming foams reported previously.1
1 S. Duan, X. Wu, K. Zeng, T. Tao, Z. Huang, M. Fang, Y. Liu, X. Min. Carbon, 2020, 159, 527
| Speaker Country | Spain |
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