Extremely low thermal conductivity and high electrical conductivity of sustainable carbon­ceramic electrospun nonwoven materials

Abstract

Materials with an extremely low thermal and high electrical conductivity that are easy to process, foldable, and nonflammable are required for sustainable applications, notably in energy converters, miniaturized electronics, and high-temperature fuel cells. Given the inherent correlation between high thermal and high electrical conductivity, innovative design concepts that decouple phonon and electron transport are necessary. We achieved this unique combination of thermal conductivity 19.8 ± 7.8 mW/m/K (cross-plane) and 31.8 ± 11.8 mW/m/K (in-plane); electrical conductivity 4.2 S/cm in-plane in electrospun nonwovens comprising carbon as the matrix and silicon-based ceramics as nano-sized inclusions with a sea-island nanostructure. The carbon phase modulates electronic transport for high electrical conductivity, and the ceramic phase induces phonon scattering for low thermal conductivity by excessive boundary scattering. Our strategy can be used to fabricate the unique nonwoven materials for real-world applications and will inspire the design of materials made from carbon and ceramic.

Engineering Covalent Heterointerface Enables Superelastic Amorphous SiC Meta-Aerogels

“…Notably, Raman spectroscopy (Figure j) revealed two prominent peaks at 1350 and 1590 cm –1 , expressly correlating to the D and G bands of carbon. In addition, the corresponding mapping image (Figure k), which illustrated the distribution of the degree of graphitization ( I G / I D ), further demonstrated the presence of free carbon in the a-SiC MAs. , …”

Colored Polymeric Films with a Bilayer Porous Design for Efficient Subambient Radiative Cooling

“…As shown in Figure 5c, the thermal conductivity of the bilayer CPRCs, including the red, green, and blue coolers, is higher than that of the PVC matrix (0.0134 W m −1 K −1 ) and even higher than the thermal conductivity of air (0.026 W m −1 K −1 ). 63 This enhancement in thermal conductivity can be attributed to the presence of BN nanoplates, which possess high thermal conductivity properties. It is demonstrated that both thermal conductivity and thermal diffusivity increase with a higher content of BN nanoplates (Figure S17), indicating that the incorporation of BN nanoplates into the composite material improves its heat conduction and transfer capabilities.…”

Evaluation of Effective Heat Transport and Temperature Gradients in Thermally Anisotropic Particulate Arrangements

“…Going beyond polymer fibers, An et al synthesized an anisotropic thermal insulation material based on a layered network of ceramic fibers . Further, Liao et al demonstrated carbon–ceramic fibers with a moderate anisotropy yet an unusual combination of electric transport and thermal insulation …”

“…17 Further, Liao et al demonstrated carbon−ceramic fibers with a moderate anisotropy yet an unusual combination of electric transport and thermal insulation. 18 Instead of building blocks with inherent anisotropy, anisotropic material properties can also be generated by a targeted arrangement or nanostructuring. One example is an insulating material fabricated via directional freeze-casting.…”