The present invention relates to a flame retardant shipping container for lithium ion batteries, and more particularly for containing a thermal runaway event. The shipping container comprising an outer box, preferably made of flame-retardant corrugated fiberboard, containing a vacuum plenum/thermal shield assembly and a tray and a first flame-retardant pouch. The assembly comprising an inner container on a thermal shield inside a metalized vacuum bag. The inner container further comprises an inner cavity and an opening and a second flame-retardant pouch. The assembly rests on the tray. The pouches contain molecular sieves and palladium plated microsphere catalysts. The thermal shield has an aluminum foil surface and is filled with thermal paste. The tray is preferably flame-retardant molded paper pulp and forms at least two pockets separated by flame-retardant molded pulp separators. The tray is separated from the outer box by an air gap containing the first flame-retardant pouch.