Fig. 6

In situ AES mapping of SEI heterogeneity. a shows an AES mapping image of the LPS SEI after 2 h of charging. b is a threshold-filter processed version of the same 2 h AES map, where white areas highlight little or no oxygen and blue areas represent higher oxygen concentrations, likely in the form of Li3PO4. c, d show the SEI after 6 and 15 h of charging, respectively