More recently, Cheng et al. have found a similar SEI component distribution using energy dispersive X-ray spectroscopy (EDS): Li 2 O is distributed throughout the SEI, and Li 3 N and Li 3 PO 4 are not in direct contact with Li but only distributed in regions closer to LiPON. These results, together with our predicted e , reinforce the idea that the SEI components with high values of e (e.g., Li 3 N) are not uniformly distributed in the SEI. Therefore, the SEI is overall electronically insulating, which enables passivation of the Li-LiPON interface.