Synergistic Improvement in the Thermal Conductivity of Hybrid Boron Nitride Nanotube/Nanosheet Epoxy Composites.

Epoxy composites with excellent thermal properties are highly promising for thermal management applications in modern electronic devices. In this work, we report the enhancement of the thermal conductivity of two different nanocomposites, using epoxy resins LY564 (epoxy 1) and LY5052 (epoxy 2), by incorporating multiwalled boron nitride nanotubes (BNNT) and boron nitride nanosheets (BNNS) as fillers. The synergistic interaction between the 1D BNNT and 2D BNNS allows for improved thermal conductivity via several different mechanisms. The highest thermal conductivity was measured at a loading of 1/30 wt % of BNNT/BNNS, resulting in values of 2.6 and 3.4 Wm-1 K-1, respectively, for each epoxy matrix. This improvement is attributed to the formation of a three-dimensional heat flow path formed through intercalation of the nanotubes between the BNNS. The thermal conductivity of the epoxy 1 and 2 nanocomposites improved by 940 and 1500%, respectively, making them suitable as thermal interface materials in electronic applications requiring electrical resistivity.

Inherent electrochemistry and charge transfer properties of few-layered two-dimensional Ti3C2Tx MXene.

We report the effect of the Ti3C2Tx MXene flake thickness on its inherent electrochemistry and heterogeneous charge transfer characteristics. It is shown that Ti3C2Tx undergoes irreversible oxidation in a positive potential window, which strongly depends on the flake thickness and pH of the electrolyte. Few-layered Ti3C2Tx exhibits faster electron transfer kinetics (k0 = 0.09533 cm s-1) with a [Fe(CN)6]4-/3- redox mediator compared to multi-layered Ti3C2Tx (k0 = 0.00503 cm s-1). In addition, the few-layered free standing Ti3C2Tx film electrode remains intact after enduring irreversible oxidation.

Engineering Nanostructural Routes for Enhancing Thermoelectric Performance: Bulk to Nanoscale.

Thermoelectricity is a very important phenomenon, especially its significance in heat-electricity conversion. If thermoelectric devices can be effectively applied to the recovery of the renewable energies, such as waste heat and solar energy, the energy shortage, and global warming issues may be greatly relieved. This review focusses recent developments on the thermoelectric performance of a low-dimensional material, bulk nanostructured materials, conventional bulk materials etc. Particular emphasis is given on, how the nanostructure in nanostructured composites, confinement effects in one-dimensional nanowires and doping effects in conventional bulk composites plays an important role in ZT enhancement.