Finally, we have investigated the Na-doping effect on the lithium vacancy generation and on the Li 2 O 2 surface decomposition. On the one hand, it is found that Na dopant reduces the lithium vacancy formation energy compared to the value for pristine surface, promoting the vacancy generation in agreement with experimental results. On the other hand, we have presented a plausible scenario to enhance lithium vacancies when the formation of the lithium peroxide occurs via a solution mechanism and Na + or K + ions are dissolved in the electrolyte.