As one of the most promising candidates to replace the conventional lithium-ion batteries with super-high capacity,non-aqueous Li-O2 batteries have attracted increasing attention [1].However,the technology is still in its infant stages and widespread commercialization is hindered by several issues,particularly low round-trip efficiency and poor cycle performance-both of which can be largely attributed to the high charge overpotential in this type of battery.This perspective is to bring up a critical issue of why the charge overpotential is so high and exhibits different rising trends.