Supercharging can't be good for the battery.
the battery design needs to be optimized around that planned charging rate. Right now, doing so hurts some other key performance parameters (nail spike heat rate among them) but battery technology will continue to improve at least as fast if not a lot faster than either ICE efficiency or fuel cell production costs.
The bigger problem with supercharging is the impact on the electric grid if it is widely adapted. It is cute to have a dozen charge plugs with a big battery hidden in the back room at a rest stop or 6 plugs connected to the main power lines at a upscale mall, but imagine if we ask every work place to offer 80 KW charge rates, at 8:15 am, the whole grid will brown out....
if everyone in your neighborhood had a Volt, there would be no infrastructure changes needed for their overnight charging. If on the other hand everyone in your neighborhood installed a 40 kw charge station, you would need to completely rewire the neighborhood. If 25 % of the people In your community installed high rate charge stations at home, you would need new substations and new high voltage feeder lines...
so there are more considerations than just the cool factor of Tesla's sleek proprietary plug.
