F-GDY and F-GDY/Graphene as anodes in lithium-ion batteries: A first-principle investigation

• The highlights have been revised as follows: Novel step-by-step adsorption energy and ab-initio molecular dynamic (AIMD) simulation are adequate to address the Li storage capacity. • A reasonable chemical potential as a function of Li number are developed and applied in estimating the Li adsorption energy. • F-GDY, by forming F-GDY/Graphene, can be an adequate component for anode materials of Li battery. The two-dimensional fluoride-substituted graphdiyne (F-GDY) and its compound layer structure, F-GDY/Graphene have been investigated as anodes in lithium-ion batteries. According to our calculation, the disadvantages of F-GDY being an anode material are its semi-conductor nature and the relatively weak mechanic strength. Fortunately, these drawbacks can be conquered by composing F-GDY with graphene sheets. The comprehensive process has been developed to evaluate capacities of anode materials. Compared with the common definition of the adsorption energy ( E ad1 ), the step-by-step adsorption energy ( E ad2 ) and ab-initio molecular dynamic (AIMD) simulation can better address the Li storage capacity. Moreover, instead of using the chemical potential of Li bulk, a more reasonable chemical potential as a function of Li number was developed and employed in estimating the Li adsorption energy on the related structures. Furthermore, the diffusivities of lithium and fluorine were also considered for both the F-GDY and the F-GDY/Graphene. The graphene layer in F-GDY/Graphene can restrict the displacement of F atoms which may lead to a more reversible charge-discharge process.