Smart money is saying it's going to be at least 5 years before there is another significant advancement in the technology that will make a difference...
The issue may be in the fact that other energy tech (fuel cell etc.) could surpass battery tech in a similar time frame...
More than one game in town.....
Want zero emissions ? Crack water, burn Hydrogen, H20 out the tailpipe........ Wash/Rinse/Repeat......
Rgds, D.