High resolution visualization of the redox activity of Li2O2 in non-aqueous media: conformal layer vs. toroid structure.

A strong relationship between the surface structure and the redox activity of Li2O2 is visualized directly using scanning electrochemical cell microscopy, employing a dual-barrel nanopipette containing a unique gel polymer electrolyte. These measurements reveal considerable local heterogeneity with significantly enhanced electrochemical activity at toroidal Li2O2 structures when compared to the conformal layer that is usually formed on the cathode of Li-O2 batteries.