Interesting, and while better batteries will help improve the cost/size/weight/life for an EV, it can't do much to change those energy efficiency numbers.
As mentioned, motors and batteries are already in the 90% plus area for efficiency, so there really just isn't much room for improvement there. Smaller, lighter batteries will help an EV get a few more miles on a charge, but this is all minor and incremental.
Also, as I've mentioned before in other threads, adding EV charging to the grid means we need to generate additional electricity to charge those EVs. Any grids with renewable energy available uses it first, as there is no additional fuel cost for that power (wind, solar, etc). And some US grids have goals of getting to 50% renewable in the next 15 years or so. But even at 50%, that's it, there is no extra to charge a fleet of EVs, they will be using all that 50% (some minor exceptions I'll detail in a moment). So even at 50% renewable grid, a fleet of EVs will require added power, and the renewable is used - so we are looking to fire up Nat Gas turbines, or maybe keep a coal plant running a little higher level through the night. So those EVs are running mostly on fossil fuel, even on a very clean grid.
The exception - if we have a lot of wind power, and since wind is on average stronger at night, and demand is down, there could be excesses from time to time, and this could cleanly recharge EVs. However, if you look at the numbers, it seems unlikely that that amount of excess would be there on a regular basis, so you still need those fossil plants available for the low and moderate wind nights. It becomes self limiting - if you have so much wind power to have regular excesses to match EV demand on moderate/low wind nights, then you will have a lot of excess on those above average (but still common) wind nights. That is energy they can't sell, raising the effective cost of all that wind power.
-ERD50