RE:Lithium could now be replacedWhen you see any article that uses the phrase " for energy storage " that means the batteries are to heavy for use in transportation . There are literally dozens of potential battery chemistries that are being developed for " energy storage applications ". There are NO batteries being developed for transportation that don't have lithium , because of the weight advantage. The one that looks the most promising is the lithium / sulfur battery that has weight and range advantages over current chemistries.