A First-Principles Investigation on the Electronic and Mechanical Properties of 1T TiSe₂ Multilayers for Energy Storage

Abstract

In this work, the electronic and mechanical properties of bulk TiSe2 were studied, and the effects of confinement on the compound, into mono-, bi-, and tri-layered systems, on the electronic and mechanical properties using DFT-based calculations within the Generalized Gradient Approximation (GGA) using Perdew–Burke–Ernzerhof (PBE) exchange-correlation functional. Lithium atoms were placed at different adsorption sites of the TiSe2 monolayer to study the consequences on the electronic and mechanical properties and to identify the most favourable adsorption site for Li in the TiSe2 systems. Mono -, bi-, and tri-layered systems have associated a metallic behaviour, similar to the bulk material. Young’s modulus for mono-, bi-, and tri-layered systems show similar behaviour to the bulk case. On the other hand, monolayers with Li are metallic when Li atoms are placed at the surface; and this behaviour could be favourable to facilitate electronic transport by the monolayer. Finally, the mechanical properties analysis supported that the better adsorption sites are those labelled as Top and Hollow.

A first-principles study of the electronic, mechanical, vibrational, and optical properties of the zirconium carbide under high pressure

“…The formulas to obtain these values can be found in many references [9,25]. The Pugh's and Poisson's ratios indicate the ductility and brittleness of a material [26]: Pugh's ratio values greater than 0.5 are linked to brittle materials, and lower values are linked to ductile materials [27][28][29]; the relevant values for the Poisson's ratio (ν) are those 0.33 for metals, while those from 0.16 to 0.30 are related to ionic-covalent compounds [27][28][29]. Vickers hardness (H V ) is a measure used to determine the hardness of a material [30], and the K, ν, and H V values can be obtained using:…”

Effects of High Hydrostatic Pressure on the Structural, Electronic, and Elastic Properties, and Li-Ion Diffusion Barrier of Lithium Lanthanum Titanate Electrolytes: A DFT Study

“…From B H and G H values, we obtained other mechanical parameters such as Pugh's criterion, Young's modulus (E), Poisson's ratio (v), and Vickers hardness (H v ) through the following equations 31,44,70,[88][89][90] :…”

“…). [90][91][92] The quantification of the mechanical resistance is obtained through the E. 31 v indicates the behaviour of the bonds in the compound, either ionic-covalent (0.16 ⩾ v ⩾ 0.30) or metallic (v ⩾ 0.33), 89 and H v indicates the SSE hardness.…”

A TiSe monolayer as a superior anode for applications of Li/Na/K-ion batteries

“…34 These properties make metal selenides a potentially promising electrode material. Metal selenides (MSe x : x = 1, 2, M = Sn, 35,36 Ni, 37 Co, 33,38 Mo, 39 Fe, 40 and Ti [41][42][43][44][45] ) have shown remarkable performance for LIBs/NIBs/KIBs. Moreover, Zhang et al 41 made a detailed introduction to TiSe 2 nanosheets for NIBs, which exhibited excellent cycling properties (115 mA h g À1 during the 500th cycle at 0.5 A g À1 ) as well as remarkable capability (103 mA h g À1 at 10 A g À1 ), owing to the shortened path for ion diffusion and an increased surface area.…”