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The development of efficient anodes for sodium‐ion batteries requires a deep understanding of the electrochemical processes involved. Herein, X‐ray spectroscopy is used to study changes in the electronic structure of MoS2 nanosheets coupled with few‐layered graphene at early stages of battery life. Working electrode is combined with a sodium plate and a solution of NaClO4 in ethyl carbonate/dimethyl carbonate in a homemade cell having an X‐ray transparent window. X‐ray absorption spectra at the S K‐edge and Mo L3‐edge are recorded using a synchrotron source, X‐ray emission S Kα and Mo Lα spectra are obtained on a laboratory spectrometer for initial powder and electrode material at different potentials of the cell. Analysis of the spectra shows the occupation of the initially empty orbitals of MoS2 by sodium electrons as a result of the interaction of the components of the sodium‐ion half‐cell. Ex situ X‐ray photoelectron spectroscopy measurements of a fully discharged electrode material reveal partial transformation of hexagonal MoS2 to disordered tetragonal MoS2 coated with a surface electrolyte interphase layer. The obtained results indicate that coupling MoS2 to graphene prevents the breaking of Mo–S bonds when Na+ ions are first introduced, which may promote stable battery performance. [ABSTRACT FROM AUTHOR]

Metal–organic framework (MOF)‐derived carbon composites have been considered as the promising materials for energy storage. However, the construction of MOF‐based composites with highly controllable mode via the liquid–liquid synthesis method has a great challenge because of the simultaneous heterogeneous nucleation on substrates and the self‐nucleation of individual MOF nanocrystals in the liquid phase. Herein, we report a bidirectional electrostatic generated self‐assembly strategy to achieve the precisely controlled coatings of single‐layer nanoscale MOFs on a range of substrates, including carbon nanotubes (CNTs), graphene oxide (GO), MXene, layered double hydroxides (LDHs), MOFs, and SiO2. The obtained MOF‐based nanostructured carbon composite exhibits the hierarchical porosity (Vmeso/Vmicro: 2.4), ultrahigh N content of 12.4 at.% and "dual electrical conductive networks." The assembled aqueous zinc‐ion hybrid capacitor (ZIC) with the prepared nanocarbon composite as a cathode shows a high specific capacitance of 236 F g−1 at 0.5 A g−1, great rate performance of 98 F g−1 at 100 A g−1, and especially, an ultralong cycling stability up to 230 000 cycles with the capacitance retention of 90.1%. This work develops a repeatable and general method for the controlled construction of MOF coatings on various functional substrates and further fabricates carbon composites for ZICs with ultrastability. [ABSTRACT FROM AUTHOR]

This article presents the first experiments on filling single‐walled carbon nanotubes (SWCNTs) with the phosphorus sulfides P4S3 and P4S10 using the ampoule method. Transmission electron microscopy examination reveals the encapsulation of phosphorus and sulfur species inside the cavities of SWCNTs without the formation of any regular structures. X‐ray photoelectron spectroscopy observes different oxidation states of P and S atoms, depending on the P/S ratio in the initial mixture used to fill the nanotubes. The Raman signals associated with the encapsulated species are low in intensity, and the vibrational modes are shifted and broadened as compared to those in crystalline P4S3 and P4S10. The proposed models for the arrangement of sulfur and phosphorus inside SWCNTs suggest the formation of 1D amorphous glassy phosphorus sulfides with stoichiometric ratios close to those of elemental phosphorus and sulfur in the initial mixtures. [ABSTRACT FROM AUTHOR]