Heh as it happens lithium is something I was using just the other day, albeit the metal, in a flask purged with argon, as a suspension in diethyl ether, sat in a cryo bath of salted ice, alcohol and antifreeze. Carefully mind you, given the great flammability of ether and the pyrophoric tendencies of the alkali metals if left to their own devices. All went without so much as a hint of warmth, though, let alone a spark, at < -20 'C (probably closer to -35 'C give or take a degree or two)