Fig. 5: Self-healing and disordered rocksalt resultant passivation.

All the TEM sequences are captured under the continuous exposure to water vapor with a pressure of P_H2O = 5 × 10⁻² Torr and at room temperature. a Pristine NMC811 covered with a saturated hydroxide film after the water vapor exposure of 30 mins with the electron beam blanked. b, c The hydroxide thickness evolution with the condense of the electron beam. The saturated LiOH layer with a thickness of h1 is completely removed after 7 s. d–f The self-healing processes at the local breaches as the weakening of electron beam. The LiOH layer recovers to the characteristic thickness after a few seconds and maintains the thickness during the subsequent 20 mins. g–i The surface evolution of NMC811 with a disordered rock salt shell. The arrow points to the disordered phase developed upon cycling, no reaction products are formed during the 30 mins water vapor exposure. j ABF-STEM images of the NMC811 after being exposed to water vapor for 30 mins. The contour of LiOH is outlined by the blue dashed lines. The inserts in j are the HAADF-STEM (left) and the corresponding ABF-STEM image (right) showing the surface with half-unit-cell-thick disordered structure and the formation of saturated LiOH layers after the water vapor exposure. The white and blue dashed lines indicate the boundaries of disordered rocksalt structure and the LiOH layers. Scale bar, 3 nm a, 2 nm g, 10 nm j, 1 nm inserts of j.