Antimony sulfide (Sb₂S₃) with a high theoretical capacity is considered as a promising candidate for Na-ion batteries (NIBs) and K-ion batteries (KIBs). However, its poor electrochemical activity and structural stability are the main issues to be solved. Herein, amorphous Sb₂S₃ nanospheres/carbon nanotube (Sb₂S₃/CNT) nanocomposites are successfully synthesized via one step self-assembly method. In-situ growth of amorphous Sb₂S₃ nanospheres on the CNTs is confirmed by X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. The amorphous Sb₂S₃/CNT nanocomposites as an anode for NIBs exhibit excellent electrochemical performance, delivering a high charge capacity of 870 mA h g⁻¹ at 100 mA g⁻¹, with an initial coulomb efficiency of 77.8%. Even at 3000 mA g⁻¹, a charge capacity of 474 mA h g⁻¹ can be achieved. As an anode for KIBs, the amorphous Sb₂S₃/CNT nanocomposites also demonstrate a high charge capacity of 451 mA h g⁻¹ at 25 mA g⁻¹. The remarkable performance of the amorphous Sb₂S₃/CNT nanocomposites is attributed to the synergic effects of the amorphous Sb₂S₃ nanospheres and 3D porous conductive network constructed by the CNTs.

NaMgH₃ perovskite hydride and NaMgH₃–carbon nanomaterials (NH-CM) composites were prepared via the reactive ball-milling method. To investigate the catalytic effect of CM on the dehydriding kinetic properties of NaMgH₃ hydride, multiwall carbon nanotubes (MWCNTs) and graphene oxide (GO) were used as catalytic additives. It was found that dehydriding temperatures and activation energies (ΔE₁ and ΔE₂) for two dehydrogenation steps of NaMgH₃ hydride can be greatly reduced with a 5 wt. % CM addition. The NH–2.5M–2.5G composite presents better dehydriding kinetics, a lower dehydriding temperature, and a higher hydrogen-desorbed amount (3.64 wt. %, 638 K). ΔE₁ and ΔE₂ can be reduced by about 67 kJ/mol and 30 kJ/mol, respectively. The results suggest that the combination of MWCNTs and GO is a better catalyst as compared to MWCNTs or GO alone.

High temperature dielectric relaxation behaviors of single phase Mn₃O₄ polycrystalline ceramics prepared by spark plasma sintering technology have been studied. Two dielectric relaxations were observed in the temperature range of 200 K–330 K and in the frequency range of 20 Hz–10 MHz. The lower temperature relaxation is a type of thermally activated relaxation process, which mainly results from the hopping of oxygen vacancies based on the activation energy analysis. There is another abnormal dielectric phenomenon that is different from the conventional thermally activated behavior and is related to a positive temperature coefficient of resistance (PTCR) effect in the temperature region. In line with the impedance analyses, we distinguished the contributions of grains and grain boundaries. A comparison of the frequency-dependent spectra of the imaginary impedance with imaginary electric modulus suggests that both the long range conduction and the localized conduction are responsible for the dielectric relaxations in the Mn₃O₄ polycrystalline samples.

To investigate Mo doping effects on the hydrogen permeation performance of Nb membranes, we study the most likely process of atomic hydrogen adsorption and diffusion on/into Mo-doped Nb (100) surface/subsurface (in the Nb₁₂Mo₄ case) via first-principles calculations. Our results reveal that the (100) surface is the most stable Mo-doped Nb surface with the smallest surface energy (2.75 J/m²). Hollow sites (HSs) in the Mo-doped Nb (100) surface are H-adsorption-favorable mainly due to their large adsorption energy (−4.27 eV), and the H-diffusion path should preferentially be HS→TIS (tetrahedral interstitial site) over HS→OIS (octahedral interstitial site) because of the correspondingly lower H-diffusion energy barrier. With respect to a pure Nb (100) surface, the Mo-doped Nb (100) surface has a smaller energy barrier along the HS→TIS pathway (0.31 eV).