A novel method and system for storing high purity hydrogen into a salt cavern is provided. Particularly, the storage process involves storing high purity hydrogen into a salt cavern without seepage or leakage of the stored hydrogen through the salt cavern walls, by creating a permeation barrier along the salt cavern walls. The cavern pressure is monitored and controlled to ensure formation and maintenance of the permeation barrier. Optional temperature treatments may also be incorporated as desired.