Figure 2
Time sequential HAADF-STEM images during a discharge-charge cycle. The blue-white-red colors are used to enhance the weak Z-contrast of the reaction products of light Li2O2. The regions with a bright white contrast represent the Li2O2 phase. (a,b) A diffuse layer with weak contrast in the vicinity of the charged electrode. (c–h) Nucleation and growth of Li2O2 nanoparticles and the formation of a network structural Li2O2 film during discharging. (i and j) The preferential dissolution of Li2O2 at the electrode/Li2O2 interface. (k–o) The decomposition of Li2O2 via the continuous dissolution of Li2O2 particles at electrolyte/Li2O2 interfaces during charging. (p) A diffuse layer around the gold electrode after the complete dissolution of Li2O2 particles. (scale bar: 100 nm, E0 = 200 keV, magnification: 50 k, dwell time: 5 μs/pixel, image size: 512 × 512 pixels, electron dose: 0.53 e−/Å2).
