Biaxial compressive strain enhances calcium binding and mobility on two-dimensional ScC: a density functional theory investigation.

In this work, we investigated calcium binding and diffusion on pristine and biaxially strained 2D ScC density functional theory calculations, for potential applications in calcium-ion batteries (CIBs). We found that 2D ScC is metallic under PBE, HSE06, and DFT+ approximation conditions, and thus can be potentially used as an electrode material for CIBs. Results showed that pristine 2D ScC adsorbs calcium modestly, with relatively low binding energy on the most stable site (0.

Prediction of sodium binding energy on 2D VS machine learning: a robust accompanying method to random structure searching.

In this work, we employed the back-propagation neural network (BPNN) for predicting the energetics of different sodium adsorption phases on the VS monolayer generated random structure searching (AIRSS). Two key adsorption features were identified as inputs: the average Na-Na distance and a defined adsorption feature marker that indicates the number of nearest-neighbor pairs within a sodium cluster. Using the stoichiometric structure NaVS as the test system, we first generated 50 random sensible structures AIRSS and optimized them density functional theory (DFT) calculations to obtain the sodium binding energy per atom.

Lithium and sodium intercalation in a 2D NbSe bilayer-stacked homostructure: comparative study of ionic adsorption and diffusion behavior.

In this work, we probed the lithium and sodium intercalation properties in monolayer-stacked NbSe bilayer homostructure configurations for their potential application as anode materials in lithium and sodium ion batteries. Similar to known monolayer transition metal dichalcogenides, such as VS, the structural phase transition barrier of NbSe from 1H to 1T is strengthened by lithium and sodium adsorption, implying that it is robust under multiple charging and discharging processes. As multi-layer, stacked 2D materials are more relevant to experiments and their intended applications, four bilayer homostructure stackings were constructed based on the alignment of Nb and Se.

First-principles investigation of the hydrogen evolution reaction on different surfaces of pyrites MnS, FeS, CoS, NiS.

We theoretically investigated hydrogen evolution reaction (HER) on the XRD observed (100), (110), (111), and (210) surfaces of pyrite structure CoS. The random structure searching method was employed in this work to thoroughly and less-biasedly identify the active sites for each considered surface. We calculated the free energy of hydrogen adsorption, and found that (110) and (210) surfaces are more active than the conventionally assumed (100) facet.

Metallic VS2 Monolayer Polytypes as Potential Sodium-Ion Battery Anode via ab Initio Random Structure Searching.

We systematically investigated the potential of single-layer VS2 polytypes as Na-battery anode materials via density functional theory calculations. We found that sodiation tends to inhibit the 1H-to-1T structural phase transition, in contrast to lithiation-induced transition on monolayer MoS2. Thus, VS2 can have better structural stability in the cycles of charging and discharging.

A first-principles examination of conducting monolayer 1T'-MX₂ (M = Mo, W; X = S, Se, Te): promising catalysts for hydrogen evolution reaction and its enhancement by strain.

We investigated the application of 1T'-MX2 (M = Mo, W; X = S, Se, Te) 2D materials as hydrogen evolution reaction (HER) catalysts using density functional theory. Our results show that 1T'-MX2 have lower energies and are dynamically more stable than their 1T counterparts, therefore likely more relevant to previous experimental findings and applications. We found that sulfides are better catalysts, followed by selenides and tellurides.

Li adsorption, hydrogen storage and dissociation using monolayer MoS2: an ab initio random structure searching approach.

Utilizing ab initio random structure searching, we investigated Li adsorption on MoS2 and hydrogen molecules on Li-decorated MoS2. In contrast to graphene, Li can be adsorbed on both sides of MoS2, with even stronger binding than on the single side. We found that high coverages of Li can be attained without Li clustering, which is essential for hydrogen storage and Li ion batteries.