Figure 5. (A) 3D-mapping images of different secondary ion fragments of the Na-stripped Bi2S3@Cu after 10 cycles at 0.5 mA cm-2 and 3 mAh cm-2; (B) Binding energy and adsorption site of PF6 on Cu (111), Bi (001), Na3Bi (001), Bi2O3 (001), Bi2S3 (110) and NaBiS2 (110).