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The influences of different parameters, such as reaction temperature, yttrium (Y) content, and H 2 concentration, on the particle size and morphological structure of Mo powder prepared via the H 2 reduction of MoO 2 , were investigated in the work. TG, XRD, FE-SEM, laser particle size analysis, model fitting, and orthogonal design experiment methods were adopted to analyze the reaction kinetic and reduction mechanism. The results showed that the optimum conditions for preparing ultrafine Mo powder were recognized as 1073 K, 1 mass% Y content, and a H 2 concentration of 0.000576 mol·cm−2·min−1, which enabled the as-prepared Mo powder with a particle size as small as 107 nm. A new interfacial chemical reaction model with the consideration of reaction temperature, H 2 concentration, and sample thickness, was proposed to analyze the reaction kinetic. It was found that the curves predicted by the model agreed well with the experimental data, with the apparent activation energy extracted to be 94.686 kJ/mol. The effect of different individual parameter on the reaction rate and the possible reduction mechanism were also elucidated. • The optimum conditions for preparing ultrafine Mo powder were obtained via an orthogonal design method. • A new interfacial chemical reaction model with the consideration of different parameters was proposed. • Both pseudomorphic transformation and chemical vapor transport mechanisms worked during the H 2 reduction process. [ABSTRACT FROM AUTHOR]

• For the first time, the porous 3D CNS/N-rGO composite was used as a lithium-sulfur battery separator with improved functions, and was coated on the separator of lithium-sulfur battery as an interlayer. • Electrode polorization of the cathode was reduced due to the improved electronic conductivity by N-rGO. • Shutter effect of the lithium-sulfur battery was suppressed by CNS/N-rGO interlayer. • The CNS/N-rGO interlayer greatly enhanced the capacity, long-term stability and rate performance (even at a high rate of 8C) of the lithium-sulfur battery. A porous composite material consisted of nitrogen-doped 3D reduced graphene oxide and evenly distributed cobalt-nickel-sulfur (CNS) nanoparticles was coated on the surface of separator serving as the interlayer between separator and electrode in lithium-sulfur battery. It delivered an initial discharge capacity of 1524 mAh g−1 at 0.1 C and a discharge capacity of 610 mAh g−1 at 8 C. The designed Li-S battery exhibited superior long-term stability. After 350 cycles tested at 1 C, it retained a capacity as high as 700 mAh g−1. It revealed that the N-dopants and decorated CNS nanoparticles in the composite could provide active sites to adsorb soluble polysulfides and accelerate the conversion of polysulfides in redox reactions, respectively, thereby suppressing the shutter effect and improving the electrochemical performance of the Li-S battery. Our strategy is promising for preparing safe and long-cycle Li-S batteries. [Display omitted] [ABSTRACT FROM AUTHOR]