Better resistance to side reactions with gel-2 is most clearly demonstrated by the Li-FeF3 full cell CE values at 1.0 mA cm -2 (Figure ). In particular, the average Li-FeF3 full cell CE for gel-1 (101 ± 3% across 50 cycles) exceeds 100%. The average full cell CE for gel-2 at 1.0 mA cm -2 , on the other hand, is 98 ± 4%. These trends reflect the fact that the LHCE is less prone to side reactions than the ILE.