•A novel method was proposed to prepare H-Si/Al.•Morphology change of Si and its effect on properties were found and explained.•H-Si/Al have excellent mechanical and thermal properties.In this paper, high-Si reinforced Al matrix composites (H-Si/Al) with Si mass ratio 50–70% were successfully fabricated from the powder mixture of Si and Al by a novel route called as powder semi-solid squeeze. It is found that no Al–Si lamellar eutectic in the composites. As the Si content increases, fine Si particles in the H-Si/Al are reduced and the coarse Si particles may increase in size, or gather together to form twisted large particles and even form a space network structure. With the Si content ranging from 50% to 70%, The flexural strength varies between 248 and 179 MPa, the mean coefficient of thermal expansion from ambient temperature to 100 °C can be regulated between 11.32 and 7.55 × 10−6°C−1, and the thermal conductivity varies between 140 and 120 W m−1 °C−1, showing that H-Si/Al prepared by powder semi-solid squeeze have excellent mechanical and thermal properties.

•P-type polycrystalline SnSe with highly preferred orientation is prepared.•Polycrystalline SnSe with highly preferred orientation has a high ZT value.•Incorporation of SnTe nanoinlusions into SnSe matrix enhances the power factor.Binary single crystal compound SnSe with high thermoelectric performance has drawn great attention to polycrystalline SnSe. Here, we synthesized highly oriented p-type polycrystalline composite samples f mol% SnTe/Ag0.005Sn0.995Se (f = 0, 0.5, 1 and 1.5) and present thermoelectric performance from 300 K to 900 K. High thermoelectric figure of merit (ZT) of the matrix Ag0.005Sn0.995Se should be attributed to highly oriented crystal grains along the (400) plane. Moreover, proper proportional (f = 0.5) incorporation of SnTe nanoinlusions into Ag0.005Sn0.995Se matrix enhances the power factor and reduces lattice thermal conductivity, which could be due to the contribution of enhanced phonon scattering resulting from abundant interfaces. Consequently, a largest ZT value of 1.6 ± 0.2 is achieved at 875 K for composite sample 0.5 mol% SnTe/Ag0.005Sn0.995Se. Furthermore, these polycrystalline composites have large values of ZT (>1) from 800 K to 900 K and good experimental repeatability, which suggests that it is a promising candidate for high temperature power generation.

SiO/reduced graphene oxide (SiO/rGO) composite was prepared by a simple hydrothermal process involving the capsulation of SiO particles with graphene hydrogel followed by the HF treatment. The prepared composite electrode exhibited higher discharge capacity and better rate capability than the pristine SiO electrode. Such enchancement could be attributed to the efficient conducting/buffering rGO matrix and the successful corrosion of SiO2 shell on the surface of SiO.

Niobium-doped lithium-rich layered cathode materials, Li[Li0.2Ni0.2Mn0.6−xNbx]O2 (x = 0, 0.02, 0.04, and 0.06), were prepared and the effects of Nb doping on the microstructure and electrochemical properties were investigated. Upon Nb doping, the layered α-NaFeO2 structure is maintained but with an expanded interlayer spacing and the electrochemical properties are significantly enhanced. In particular, the sample with x = 0.04 delivers a large reversible discharge capacity of 254 mA h g−1 at 0.1 C rate with a high capacity retention rate of 92.3% after 100 cycles. Furthermore, it delivers 198 mA h g−1 at 1 C rate, much larger than that of the undoped sample (125 mA h g−1). Capacity differential results reveal that strong Nb–O bond can stabilize the material structure and thus lead to a stable cycling performance. Electrochemical impedance spectroscopy (EIS) analysis shows that Nb doping can decrease the whole cell impedance and expand the Li+ diffusion path in the lithium-rich layered cathode materials, resulting in the excellent rate capability.

•Solid-state processing reaction technique was used to prepare ZnxNb1−xO bulk samples.•The transport and thermoelectric properties for all samples were investigated.•The intrinsic acceptors like the zinc vacancy can trap electrons.•The Nb2O5 addition is fairly effective for enhancing thermoelectric properties.Solid-state reaction processing technique was used to prepare ZnxNb1−xO (0≤x≤0.02) polycrystalline bulk samples. In the present study, we find that their lattice parameters a and c tend to decrease with increasing amount of Nb additive. The electrical conductivity of all the Zn1−xNbxO samples increased with increasing temperature, indicating a semiconducting behavior in the measured temperature range. The addition of Nb2O5 to ZnO led to an increase in the electrical conductivity and a decrease in the absolute value of the Seebeck coefficient. The best performance at 1000 K has been observed for nominal 0.5 at% Nb-doped ZnO, with an electrical resistivity of about 73.13 (S cm−1) and Seebeck coefficient of ∼257.36 μV K−1, corresponding to a power factor (S2σ) of 4.84×10−4 Wm−1 K−2. The thermal conductivity, κ, of the oxide decreased as compared to pure ZnO. The figure of merit ZT values of ZnO-doped Nb2O5 samples are higher than the ZnO pure sample, demonstrating that the Nb2O5 addition is fairly effective for enhancing thermoelectric properties.