I agree that batteries are the future. I don't know what hurdles are still there. Are those sugar batteries rechargeable? Do they work at low temperatures? Regardless even once we solve the problems with batteries there is still the issue of power generation. I am a strong believer that the only technolgy that is going to produce a sufficient amount of clean power to meat our demand is nuclear power. Until we embrace nuclear power and start to replace our coal and gas fired plants on a large scale the electric car is going to do very little to reduce our green house gas emissions.
As near as I can tell, the batteries are not rechargeable in the conventional sense. When the sugar level gets too low, you just drain the battery reservoir and refill it with new sugar solution. At this time, I don't know if the battery requires a certain time to get back to full power. The impression I get is that this is not a serious problem. The big thing is that the waste, the worn out sugar solution, is completely biodegradable.
I agree that automobiles are only part of the problem. Power generation from coal fired plants is not the answer. . At the moment, nuclear power seems to be the only way to go.