Fig. 4: Passivation layers evolution with the presence of CO2.
From: Unlocking the passivation nature of the cathode–air interfacial reactions in lithium ion batteries

a The surface of NMC811 after exposed to water vapor (PH2O = 5 × 10−2 Torr) for 30 mins, indicating a uniform passivation layer of LiOH. The black lines outline the boundary of LiOH. b The surface morphology of NMC811 after the water vapor exposure and followed by exposure to CO2 for 10 mins (PCO2 = 5 × 10−2 Torr), leading to the formation of Li2CO3. The blue dashed lines outline the boundary of each Li2CO3 island. Scale bar, 5 nm a, b.