Non-aqueous Li-air or Li-O 2 cells show considerable promise as a very high energy density
battery couple. Such cells, however, show sudden death at capacities far below their
theoretical capacity and this, among other problems, limits their practicality. In this paper, we
show that this sudden death arises from limited charge transport through the growing Li 2 O
2 film to the Li 2 O 2-electrolyte interface, and this limitation defines a critical film thickness,
above which it is not possible to support electrochemistry at the Li 2 O 2–electrolyte …