This sounds interesting, but I'm not sure how one would do that? Are you saying that the EVSE that comes with the Volt (that I am presently using with a 120V plug) can be used with 240V without hurting anything? Does it charge fast like a Level 2 EVSE?
The 120v EVSE that came with your car is a Clipper Creek that accepts both 120v and 240v. However, GM does not supply adapters to run them off 240v.
Max charging with a Gen 2 Volt is 240v x 16 amps. The factory portable 120v EVSE will operate at 240v x 12 amps. So it will charge at 3/4th the speed of 16 amp (or higher) EVSE. So about 6.5 hours for a full charge depending on your actual voltage.
First you need a 240 volt outlet, or two 120v volt outlets that use different hots. Your house is a 3 wire house. Two wires are hots at 120v and one is a neutral. The neutral is the fat blade of a 120v plug.
If you take the two different hots and check their voltage against each other, you'll see 240 volts. So if one wall socket uses one hot, and another uses the second hot, if you touch the two thin blades, you'll see 240v. So you make a Y connector from parts at Home Depot. A female 120v plug, and 2 male 120v plugs.
There is somebody on this site who used to make adapters. Try doing a search.