There is another scenario in which dissolved Na + can promoted lithium vacancies. If an electrolyte with high donor number is used in the experiment, as was the case of Ref. 29, the solution mechanism of Li 2 O 2 formation in the LOB is more likely. Considering the solution mechanism, two LiO 2 dissolved in the electrolyte disproportionate to form Li 2 O 2 releasing one O 2 molecule. As mentioned before, the doping with K + has also been probed to promote the tendency to O - 2 and the generation of lithium vacancies. In general, when a cation X is dissolved in the electrolyte, the following disproportionation