High‐Pressure High‐Temperature Synthesis of MoS₂/Holey Graphene Hybrids and Their Performance in Li‐Ion Batteries

Abstract

Hybrids of holey graphene (HG) and MoS 2 have been prepared by a treatment of few-layered HG and amorphous MoS 3 , taken in a weight ratio of %5 and %10%, at 100 bar and 600 C under vacuum. A study of the products by electron microscopy, X-ray diffraction, Raman scattering, and X-ray photoelectron spectroscopy has detected coating of graphene stacks by thin MoS 2 layers. The near-edge X-ray absorption fine structure spectroscopy has revealed a covalent bonding between MoS 2 and HG components. A hybrid with 5 wt.% of MoS 2 showed a better rate capability for Li-ion intercalation/ deintercalation as compared to the isolated HG and a hybrid with a higher MoS 2 loading. Owing to the electrochemical impedance spectroscopy measurements, this was attributed to a faster charge transport in the hybrid with the thin MoS 2 coating.

Nanocarbon Photonics and Optoelectronics

“…The productive discussions during the meeting (which has been held on 19–24 March 2017) were provided by perfect organization and nice natural environment, including ski slopes, at Krasnaya Polyana resort (Sochi, Russia). The contributions (in total an amount of 30) of this Special Issue are covering research work related to production, characterization and application of the nanocarbon materials which include diamonds, carbon nanotubes, graphene other types of nanocarbon materials, and their composites . Traditionally for the NPO Workshop series there is also some portion of reports devoted to non‐carbon materials demonstrating properties and phenomena analogous to those observed for nanocarbons.…”

Pressure‐Assisted Interface Engineering in MoS2/Holey Graphene Hybrids for Improved Performance in Li‐ion Batteries

“…The low temperature was chosen according to the DTG curve, which showed that MoS 3 transforms to MoS 2 between 385 and 450 °C (Figure ). The XRD analysis of 30MoS 2 /HG400a and 30MoS 2 /HG500a (Figure a) detected reflections from the HG planes and the planes of hexagonal MoS 2 . This confirms the crystallization of MoS 2 at the temperatures used.…”

“…All spectra have two main peaks located at ≈285.5 and ≈292.8 eV and assigned to 1s → π* and 1s → σ* electron transitions, respectively. The peaks appearing between these resonances are usually due to functionalized carbon atoms . They have a negligible intensity in the HG600a spectrum indicating that the treatment conditions lead to the removal of oxygen groups, which were present in the initial HG sample (Figure S5, Supporting Information).…”

“…The treatment of MoS 3 /HG or HG was carried out in a sealed chamber of the setup described elsewhere . A sample was held between punches with a diameter of 10 mm into a graphitic mould.…”

Effect of Hot Pressing on the Electrochemical Performance of Multilayer Holey Graphene Materials in Li‐ion Batteries

“…Moreover, the edge carbon atoms, constituting the boundaries of the holes, may work as the sites for anchoring of redox‐active substance on the graphene plane. Hot pressing of such composites improves the bonding between the components that causes decrease of the resistance for charge transport in Li‐ion cells . However, before the development of synthesis procedures for such hybrids, it is necessary to find the limiting values of pressure and temperature, which do not degrade the electrochemical characteristics of the HG component.…”