“…We chose SnCl 2 as an additive because of its well‐established reducing activity in organic chemistry. Surprisingly, its electronic properties as an anhydrous solid do not appear to have been measured, nor has its in situ microcrystallization in polymer environments been observed; the closest precedent being hydrated proton conductors . Other tin‐based materials have previously been investigated as potential TE materials, experimentally and through computation, including pure tin films, tin oxides, tin selenides, tin clathrates, and tin sulfide, or as beneficial TE impurities in telluride‐based inorganic materials …”