As a high-temperature thermoelectric (TE) material, ZnO offers advantages of non-toxicity, chemical stability, and oxidation resistance, and shows considerable promise as a true ready-to-use module under air conditions. However, poor electrical conductivity and high thermal conductivity severely hinder its application. Carbon nanotubes (CNTs) are often used as a reinforcing phase in composites, but it is difficult to achieve uniform dispersion of CNTs due to van der Waals forces. Herein, we developed an effective in-situ growth strategy of homogeneous CNTs on ZnO nanoparticles by exploiting the chemical vapor deposition (CVD) technology, in order to improve their electrical conductivity and mechanical properties, as well as reducing the thermal conductivity. Meanwhile, magnetic nickel (Ni) nanoparticles are introduced as catalysts for promoting the formation of CNTs, which can also enhance the electrical and thermal transportation of ZnO matrices. Notably, the electrical conductivity of ZnO is significantly boosted from 26 to 79 S·cm⁻¹ due to the formation of dense and uniform conductive CNT networks. The lattice thermal conductivity ( ${\kappa }_{\text{L}}$) is obviously declined by the intensification of phonon scattering, resulting from the abundant grain boundaries and interfaces in ZnO–CNT composites. Importantly, the maximum dimensionless figure of merit (zT) of 0.04 at 800 K is obtained in 2.0% Ni–CNTs/ZnO, which is three times larger than that of CNTs/ZnO prepared by traditional ultrasonic method. In addition, the mechanical properties of composites including Vickers hardness (HV) and fracture toughness $(K_{\text{IC}})$ are also reinforced. This work provides a valuable reference for dispersing nano-phases in TE materials to enhance both TE and mechanical properties.

The X band (8 GHz–12 GHz) is the electromagnetic wave band emitted by most electronic instruments in our life, which will cause electromagnetic pollution harm to human health. Due to the coexistence of magnetic loss and dielectric loss, the modified Fe₃O₄-carbon-based nanomaterial exhibit strong electromagnetic (EM) wave absorptive capacity. However, there is a problem that the effective absorption bandwidth (EAB, the frequency bandwidth of reflection loss is less than −10 dB) of the X band is narrow. Increasing the EAB value of Fe₃O₄-carbon-based materials is of great significance for reducing electromagnetic pollution. Here, an emulsion-based self-assembly technique and ligand carbonization treatment have been used to construct the Fe₃O₄@C supraparticles for the evaluation of EM performance. The Fe₃O₄@C supraparticles exhibit excellent EM absorption properties, which can achieve full coverage of X band from 6.52 GHz to 12.9 GHz at a sample thickness of 3 mm. Besides, the optimum EAB value of Fe₃O₄@C supraparticles is up to 8.55 GHz from 9 to 18 GHz at a sample thickness of 2.5 mm. The Fe₃O₄@C supraparticles with superlattice structure will have potential development prospects in the application of broadband absorption.

N-type Se&Lu-codoped Bi₂Te₃ nanopowders were prepared by hydrothermal method and sintered by spark plasma sintering technology to form dense samples. By further doping Se element into Lu-doped Bi₂Te₃ samples, the thickness of the nanosheets has the tendency to become thinner. The electrical conductivity of Lu_0.1Bi_1.9Te_3-xSe_x material is reduced with the increasing Se content due to the reduced carrier concentration, while the Seeback coefficient values are enhanced. The lattice thermal conductivity of the Lu_0.1Bi_1.9Te_3-xSe_x is greatly reduced due to the introduced point defects and atomic mass fluctuation. Finally, the Lu_0.1Bi_1.9Te_2.7Se_0.3 sample obtained a maximum ZT value of 0.85 at 420 K. This study provides a low-cost and simple low-temperature method to mass production of Se&Lu-codoped Bi₂Te₃ with high thermoelectric performance for practical applications.

A broad tunability of the thermoelectric and mechanical properties of CoSb₃ has been demonstrated by adjusting the composition with the addition of an increasing number of elements. However, such a strategy may negatively impact processing repeatability and composition control. In this work, single-element-filled skutterudite is engineered to have high thermoelectric and mechanical performances. Increased Yb filling fraction is found to increase phonon scattering, whereas cryogenic grinding contributes additional microstructural scattering. A peak zT of 1.55 and an average zT of about 1.09, which is comparable to the reported results of multiple-filled SKDs, are realized by the combination of simple composition and microstructure engineering. Furthermore, the mechanical properties of Yb single-filled CoSb₃ skutterudite are improved by manipulation of the microstructure through cryogenic grinding. These findings highlight the realistic prospect of producing high-performance thermoelectric materials with reduced compositional complexity.