Using first-principles calculations, we evaluate the electrochemical performance of heterostructures made up of ${\mathrm{Ti}}_2{\mathrm{CO}}_2$ and chemically modified graphene for $\mathrm{Li}$ batteries. We find that heteroatom doping and molecule intercalation have a significant impact on the storage capacity and $\mathrm{Li}$ migration barrier energies. While N and S doping do not improve the storage capacity, B doping together with molecule interaction make it possible to intercalate two layers of $\mathrm{Li}$, which stick separately to the surface of ${\mathrm{Ti}}_2{\mathrm{CO}}_2$ and B-doped graphene. The calculated diffusion-barrier energies ($E_{\mathrm{diff}}$), which are between 0.3 and 0.4 eV depending on $\mathrm{Li}$ concentration, are quite promising for fast charge and discharge rates. Besides, the predicted $E_{\mathrm{diff}}$ as much as 2 eV for the diffusion of the $\mathrm{Li}$ atom from the ${\mathrm{Ti}}_2{\mathrm{CO}}_2$ surface to the B-doped graphene surface significantly suppresses the interlayer $\mathrm{Li}$ migration, which diminishes the charge and discharge rates. The calculated volume and lattice parameter changes indicate that ${\mathrm{Ti}}_2{\mathrm{CO}}_2/$graphene hybrid structures exhibit cyclic stability against $\mathrm{Li}$ loading and unloading. Consequently, first-principles calculations we perform evidently highlight the favorable effect of molecular intercalation on the capacity improvement of ion batteries.

• Received 14 November 2018
• Revised 25 April 2019

DOI:https://doi.org/10.1103/PhysRevApplied.12.014001