> "Given that practical lithium-ion batteries were capable of achieving energy-densities of 113Wh/kg in 1994, 202Wh/kg in 2004, and are now capable of approxima

> "Given that practical lithium-ion batteries were capable of achieving energy-densities of 113Wh/kg in 1994, 202Wh/kg in 2004, and are now capable of approximately 300Wh/kg, it’s reasonable to assume that they will hit 400Wh/kg in the coming decade." -Elon Musk http://www.aviation.com/general-aviation/elon-musk-toying-designs-electric-jet/ http://www.aviation.com/general-aviation/elon-musk-toying-de...