First principles study of layered transition metal dichalcogenides for use as electrodes in Li-ion and Mg-ion batteries

Abstract

We present a first principles investigation of lithium- and magnesium-intercalation into each of the layered transition metal dichalcogenides. Using a consistent and thorough methodology, we investigate 84 TMDC materials (transition...

Intercalation-dependent elastic properties of transition metal dichalcogenides

“…Though the intercalation of an arbitrary species into the vdW gap must overcome the endothermic expansion of layers, Group I and II species offer a significant electron donation to the host TMDC (in particular, to the X species). In our previous work, 25 we identified a large charge transfer of 0.86 electrons from lithium and 1.63 electrons from magnesium. The larger charge donation allows for bonding of a more ionic nature between an intercalant with a large positive charge (Li or Mg) and the chalcogen with a very negative charge, in place of the weak vdW bonding across the gap.…”

“…63 Intercalant ions were introduced into the vdW spacing, choosing the octahedrally-coordinated site above the metal atom of the host structure as this has been shown in a previous work to be the lowest in energy. 25 The modelled structure are illustrated in Fig. 1.…”

Properties of Layered TMDC Superlattices for Electrodes in Li-Ion and Mg-Ion Batteries

“…Thus, the minimal expansion demonstrated by layered materials holds upon construction of the superlattice, with most superlattices expanding by less than 20% (30%). These values are comparable with other layered materials that have demonstrated success as intercalation electrodes, including LiCoO 2 , (2–3.25%), NMC (8.44%), and graphite (13.2%), as well as the <30% generally seen for the TMDCs …”

“…Following the work of Whittingham , and Goodenough , in the 1970s and 1980s and the recent isolation of graphene by Novoselov and Geim, , materials which possess a layered structure have received a lot of attention for energy storage. Materials such as NMC and its variants, − the TMDCs, − and the MXenes − all demonstrate ideal electrode properties owing to the fact that their intrinsic structures possess van der Waals (vdW) gaps and provide natural channels for intercalated ions to occupy and travel through during the cycling of a cell. However, many of these materials possess voltages that lie outside ideal anode/cathode ranges, slow charging rates, and low capacities.…”

Computational Study of the Enhancement of Graphene Electrodes for Use in Li–Ion Batteries via Forming Superlattices with Transition Metal Dichalcogenides

“…Many electrode materials share the layered structure of transition metal dichalcogenides (TMDCs), which are made of one part transition metal (M) and two parts chalcogen (S, Se, or Te, denoted as X) with the general formula MX 2 . Since the investigations into TiS 2 , − TMDCs have remained a prevalent electrode, − with sulfur-based TMDCs often being looked at over other TMDCs as they are lighter and have been shown to have higher capacities than selenium- and tellurium-based TMDCs . The large van der Waals gap TMDCs possess allows for the rapid insertion and extraction of intercalants, as demonstrated by systems such as VS 2 , while maintaining relatively low volume changes of 8% for materials such as NMC .…”