In this study, force field based simulations are employed to examine the defects, Li-ion diffusion pathways together with activation energies and solution of dopants in Li2Ti6O13. The lowest defect energy process is found to be the Li Frenkel (0.66 eV/defect) inferring that this defect process is most likely to occur. This study further identified that cation exchange (Li-Ti) disorder is the second lowest defect energy process. Long range diffusion of Li-ion is observed in the bc plane with activation energy of 0.25 eV inferring that Li-ion moves fast in this material. The most promising trivalent dopant at the Ti site is Co3+ that would create more Li interstitials in the lattice required for high capacity. The favourable isovalent dopant is the Ge4+ at the Ti site that may alter the mechanical property of this material. The electronic structures of the favourable dopants are analyzed using density functional theory (DFT) calculations.