Wiktionary
lithium peroxide
n. (context inorganic compound English) The compound Li2O2 that is used to remove carbon dioxide from air and replace it with oxygen
Wikipedia
Lithium peroxide
Lithium peroxide is the inorganic compound with the formula Li O. It is a white, nonhygroscopic solid. Because of its low density, the solid has been used to remove CO from the atmosphere in spacecraft.