Investigation on TiS2 electrode material for intercalation batteries, namely Li, Na, Mg, Al, K, Ca, and Zn -ion cells: A DFT study

This paper analytically evaluates LiTiS2, NaTiS2, MgTiS2, AlTiS2, Al0.5TiS2, KTiS2, CaTiS2, and ZnTiS2 electrode materials, via DFT calculations, to use in Li-, Na-, Mg-, Al-, K-, Ca-, and Zn- ion intercalation batteries. The structural properties and stability, electrochemical, and electrical properties are investigated. For each battery, one (and two for Al-ion) intercalated structure alongside with two deintercalated structures are assessed, for the first and other cycles separately. Two approximation methods, GGA and GGA + U, are performed; which, three values of U (i.e. 2.1, 3.5, and 5.5) are taken into account. Structural parameters, internal and Fermi energies, DOS, band structure, and electron density are evaluated. Novel approaches are used for voltage, band-gap, and rate-capability; in which, for each property, two approaches are considered, namely, Fermi/Internal-energy, ILBG/ELBG, and Delta/CCTB, respectively. Our results show that K- and Ca- ion cells may face some challenges regarding electrical rate-capability and structural stability. Furthermore, the paper depicts that TiS2 electrode can represent superior properties for some intercalation batteries. It performs a comprehensive theoretical investigation on the layered TiS2 electrode material to comprehend its behaviour/properties, broadening insights for assessing different intercalation batteries.