Intercalation in 2H-TaSe 2 for modulation of electronic properties and electrochemical energy storage

TL;DR

This paper investigates how intercalating lithium, sodium, and potassium into 2H-TaSe2 modifies its electronic structure and explores its potential for electrochemical energy storage applications.

Contribution

It introduces the effects of alkali metal intercalation on 2H-TaSe2's electronic properties and assesses its suitability for energy storage, combining experimental and theoretical analyses.

Findings

Intercalation induces a 1 eV band gap in 2H-TaSe2.

Modified band structure suggests potential for energy storage applications.

Multi orbital electron-electron correlations are significant in intercalated TaSe2.

Abstract

Two-dimensional transition metal dichalcogenides (TMDs) exhibit an extensive variety of novel electronic properties, such as charge density wave quantum spin Hall phenomena, superconductivity, and Dirac and Weyl semi-metallic properties. The diverse properties of TMDs suggest that structural transformation can be employed to switch between different electronic properties. Intercalation and zero valence doping of molecules and atoms into the van der Waals gap of TMDs have emerged as effective approaches to modify the charge order states of the material. This eventually leads to phase transition or the formation of different phases, thus expanding the electronic, thermoelectric and optical applications of these materials. In this study, electronic and electrochemical energy storage properties of such an intercalated TMD, namely, 2H-TaSe 2 via intercalation of lithium (Li), sodium (Na) and potassium (K) have been investigated. The intercalation of these ions into the dichalcogenide resulted in a modified band structure and novel structural effects, leading to the emergence of a 1 eV band gap. Possibility of electrochemical energy storage application is also explored in this study. Furthermore, the importance of multi orbital electron-electron correlations in intercalated TaSe 2 is also investigated via dynamical-mean-field theory with local density approximation.