It seems like the actual value add here is the long-term storage, Why not use aluminum? Lithium (Li): 3,860,000 joules/kg Aluminum (Al): 31,500,000 joules/kg C

It seems like the actual value add here is the long-term storage, Why not use aluminum? Lithium (Li): 3,860,000 joules/kg Aluminum (Al): 31,500,000 joules/kg Copper (Cu): 13,100,000 joules/kg Iron (Fe): 20,000,000 joules/kg Nickel (Ni): 9,800,000 joules/kg Titanium (Ti): 10,500,000 joules/kg Zinc (Zn): 3,700,000 joules/kg Lead (Pb): 2,040,000 joules/kg Silver (Ag): 10,490,000 joules/kg Gold (Au): 9,700,000 joules/kg It has the highest density per joules/kg.