Room-temperature sodium-sulfur (RT Na-S) batteries are arousing great interest in recent years. Their practical applications, however, are hindered by several intrinsic problems, such as the sluggish kinetic, shuttle effect, and the incomplete conversion of sodium polysulfides (NaPSs). Here a sulfur host material that is based on tungsten nanoparticles embedded in nitrogen-doped graphene is reported.
View Article and Find Full Text PDFLithium-sulfur (Li-S) batteries, as part of the post-lithium-ion batteries (post-LIBs), are expected to deliver significantly higher energy densities. Their power densities, however, are today considerably worse than that of the LIBs, limiting the Li-S batteries to very few specific applications that need low power and long working time. With the rapid development of single cell components (cathode, anode, or electrolyte) in the last few years, it is expected that an integrated approach can maximize the power density without compromising the energy density in a Li-S full cell.
View Article and Find Full Text PDFThe Ge/Si(001) system has been analysed by grazing-incidence X-ray diffraction on a standard laboratory X-ray diffraction tool. A periodic array of interfacial edge dislocations forms a coincidence site lattice (CSL) which yields equidistantly spaced satellite peaks close to Bragg peaks of the Ge layer and Si substrate. The diffraction behaviour of the CSL was analysed using 2θ/φ scans along [100], [110] and [310] directions as well as azimuthal φ scans which revealed a 90° angular symmetry of the CSL.
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