"Tantalum is the most important element you've never heard of", page-3

Dont forget lithium. The future of lithium still looks very good because one company failed due to bad management that should not reflect on lithium the demise of that company was nothing to do with the product.

The majority of our energy will be delivered not through fossil fuels but through Lithium a very special metal.
It's the lightest of all metals known to man, and it's also used in alloys to strengthen and lighten things like aircraft. It's a key component of modern batteries, particularly the rechargeable kind.
Your cell phone. There are billions out there today, and each and every one of them contains some of this metal.
With the market for large, rechargeable batteries now hitting record growth figures and even more growth expected for at least the next decade, this element is rapidly becoming one of the most important industrial metals there is.
There's more and more demand for Lithium. This demand comes from almost everything . From cell phones to portable computers to tablets, tools, lighting, gadgets, toys, gps, cameras, lawn mowers, whipper snippers , chainsaws, ebikes, starter batteries, and all the way up to hybrid and pure electric vehicles, everything that needs compact, rechargeable power sources relies on lithium the way we rely on water and oxygen.
Not since the adoption of gasoline as a general power source has any commodity been this universally needed.
The conclusion is simple: Lithium is THE energy investment of the 21st century, more so than any other — including oil, natural gas, nuclear, solar, as well as any and all of the industries that support those.
And with Tesla's "Gigafactory" now being built and promising to nearly double the entire world's rechargeable battery production capacity, that demand is only now starting to ramp up.
Energy is energy, and in the coming decades, lithium's importance will be growing more and more.