Lithium Ion cells have a power to weight advantage over other types of rechargeable batteries, but they are very temperamental. This gives the ones you find in electronic devices such as phones, cameras, mp3 players and laptop computers have some advantages. In these types of application they can perform admirably.
When you try to use Lithium Ion cells in applications where you are storing and discharging greater amounts of power with higher voltages and amperage like in a car or even a scooter... the challenges are far greater and the temperamental nature of the individual cells becomes much more problematic and sometimes even dangerous. After one gets their hands a little dirty working with these cells it is not hard to imagine how it could take vast amounts of money find practical ways to use them in this type of application.
For example: If you are using just two cells in series and they are not well matched during charging and discharging and one of the cells is either overcharged or especially if it is allowed to be discharged too far... you find yourself with a permanently damaged battery. It is very easy to do. Often one cell used in series will discharge almost completely while the other cell still has lots of power left.
Even using them in small flashlights incorrectly can end up destroying many cells if you are not paying very close attention and checking on them frequently. I know they are spending millions trying to perfect lithium ion batteries for transportation uses, but they may never be truly practical or economical. There are good reasons why unlike Ni-cads, and NIMH cells, Li-Ion cells can not be found in your neighborhood convenience store.
Sorry to ramble on... but I don't think most people appreciate the challenges involved in using Li-Ion cells in all electric vehicles. I am skeptical that the governments goals will be met.
I haven't checked convenience stores lately but you can buy them at Walmart, Radio Shack, Home Depot, Rite-Aid, Walgreens ....