Theoretical studies of lithium storage properties of novel two-dimensional carbides

Abstract

MXenes are a new series of two-dimensional (2D) carbides or nitrides. Lithium storage properties and lithiated structures of three MXenes phases, Ti2C, V2C, and Nb2C, are studied by density functional theory. Additionally, the influence of fluorine functional groups on the lithiated structures and properties are also investigated. By calculating the adsorption energy, density of state, and charge population, we observe that double Li atom layers can be adsorbed on the surfaces of MXenes. For Ti2C, V2C, and Nb2C, the calculated maximum Li capacities reach values up to 995.04, 941.31, and 541.93 mAh g–1, respectively. Fluorine functional groups are observed to effectively enhance the stability and conductivity of the lithiated structures of these three 2D crystals.