Effect of oxygen adsorbability on the control of Li₂O₂ growth in Li-O₂ batteries: Implications for cathode catalyst design

Understanding and controlling the growth of the vital Li₂O₂ product, which is associated with intrinsic property of cathode surface, is essential to design effective cathode catalysts in Li-O₂ batteries. Herein we establish the correlation between the Li₂O₂ growth model and the O₂ adsorbability on cathode surface that determines the pathway of the first electron transfer to O₂. The weak O₂ adsorbability drives the solution growth model to form Li₂O₂ toroid, while the strong one drives the surface growth model to thin film. Based on this mechanism, we select the N-doped carbon nanocages as cathode to realize a simultaneous large discharge capacity and low charge overpotential by forming copious thin-film Li₂O₂, deriving from its high specific surface area and enhanced O₂ adsorbability due to N-doping. Our study demonstrates an effective strategy to design advanced cathode catalysts in Li–O₂ batteries and potentially other metal-air batteries.