Electric cars charge via J1772 charging stations. This would tend to make it look like electric cars cannot use the ubiquitous 120 volt power outlets.
All the electric cars come with 120 volt capable J1772 EVSE's that charge the electric car at a slow rate.
However, there's options ..
http://evseupgrade.com will upgrade a Nissan Leaf or some other 120 volt EVSE's to run at 240 volts. They can even upgrade it to run 16 amps 240 volts, which works out to the same 3.3 kilowatt rate on most of the electric cars. It won't support the 6.6 kilowatt rate on e.g. the Ford Focus Electric or Coda.
That's great if you have a 240 volt outlet available. Those are rare in the U.S. A gizmo at http://quick220.com can glue together two 120 volt power outlets to make an 240 volt outlet. You have to carefully select the power outlets so that they are on opposite phases.
More details here:-