From the bulk calculation, it is observed that the DFT+U correction is not able to reproduce the band-gap value of other more precise calculation techniques such as HSE or scGW. Furthermore, it is shown that a minimum value of U = 8 eV is necessary to stabilize the hole polarons and avoid spurious metallic solutions. In turn, these unphysical large values of U affect dramatically the formation energy and migrations barriers of the intrinsic defects, which could lead to wrong interpretations of the charge transport in the Li 2 O 2 . Regarding the calculations of the Li 2 O 2 surface energies, the thermodynamic description obtained with DFT+U is different from that obtained with both GGA and HSE. This difference could be ascribed to the artificial reconstructions induced by the high U required to stabilize the polaron.