It's not just the disposal of the batteries, it's the manufacture of them. Once you factor in the environmental impact of making the car, it's not yet proven that something like the Prius is better. I'm not sure how that would work with pure electric cars, but like I said, you've then got to factor in the environmental cost of the electricity you're powering the car with.

I don't know what happens to the technologies you're referring to, and it's difficult to find out without knowing specifically which you're referring to. As a generalisation, economic viability will kill ideas without needing a conspiracy to suppress it. You also have to consider that anything replacing the petrol engine has to fit in with how we use it. A fifteen minute recharge time couple with a sufficient range could do that. The Tesla as it was, not so much. Ok, a couple of hundred miles isn't bad range, but then you have to stop for several hours. Fine for nipping into town and back, but not what you want on a longer drive.

 

Wow, a Porsche that would have to yield to shittier cars on the 'bahn.
Beep! Beep! *double flash of headlights*
I know i didn't just get passed by souped up Gremlin...