Random article[1] says: > our guideline real-world figure of 1.4 kg of Li2CO3 per kWh > 73 grams of Lithium metal .. equates to 385 grams of Li2CO3. Adjustin

Random article[1] says: > our guideline real-world figure of 1.4 kg of Li2CO3 per kWh > 73 grams of Lithium metal .. equates to 385 grams of Li2CO3. Adjusting for atomic mass difference, by data from an article[1], a 100kWh battery would be about 100 * 1.4kg * 73g/385g = 27 kg of Lithium, or 27 kg * 19/7 = 73 kg of potassium for a 46kg difference, if all else were equal. If that were the only difference, it would not even register for the usual 1000-2000 kg car. Electronegativity difference 0.98-0.82 = 0.16 should (I'm just guessing) change a 3.7V nominal battery to a 3.55V nominal. This a notable decrease, as you would need about 5% more batteries for the same capacity. 5% of a 500kg battery pack is additional 25 kg. All else being equal, it would be an irrelevant change for stationary, marine and road use. For planes it would be a notable factor, though not immediately disqualifying. Since a 1:1 substitution wont work, all the other changes can make a material difference, in either direction. Comments about research batteries still apply. [1] http://www.meridian-int-res.com/Projects/How_Much_Lithium_Per_Battery.pdf http://www.meridian-int-res.com/Projects/How_Much_Lithium_Pe... EDIT: Fix calculation.