Theoretical study on single-side fluorinated graphene for lithium storage

Abstract

Fluorinated graphene and its derivatives have been widely applied as anode materials in energy batteries nowadays. In this work, we systematically study the case of lithium atoms absorbed on fluorine-free side of single-side fluorinated graphene (CnF) with varied fluorine contents (n = 2, 6 and 8) by density functional theory simulations. The surfaces of fluorine-free side of CnF are all energetically favorable for adsorption of lithium. Systematic analysis on the electronic properties of Li-CnF structures are performed by differential charge density, Bader charge transfer and electron projected density of states. Among the three structures, C2F exhibits an excellent lithium storage performance, with extremely low lithium ion diffusion barrier (0.04 eV), high open circuit voltage (0.96 V) and acceptable maximum lithium storage capacity (623 mAh/g). Our results suggest that the single-side fluorination of graphene is a promising approach for lithium storage.