Source : Webster's Revised Unabridged Dictionary (1913)

Expansile \Ex*pan"sile\, a.
   Expansible.

         Ether and alcohol are more expansile than water.
                                                  --Brande & C.

Source : WordNet®

expansile
     adj : (of gases) capable of expansion [syn: {expandable}, {expandible},
            {expansible}]