A separator rich in SnF2 and NO3− directs an ultra-stable interface toward high performance Li metal batteries

This separator abundant in SnF 2 and NO 3 − can form an ultra-stable SEI rich in LiF, Li 5 Sn 2 , LiN x O y and Li 3 N, while featuring a positively charged framework to immobilize the anion to facilitate Li + transport, contributing to high-performance LMBs.