As investors start to lose faith in Tesla Motors TSLA -1.01% and its battery-powered future, some of the more brazen claims for electric cars generally are starting to look a bit ambitious.

But as battery-only sales tread water, hybrids, free of the range anxiety curse, will spurt ahead.

Too much faith has been put in the development of lithium ion batteries, according to Donald Sadoway, Professor of Materials Chemistry at the Massachusetts Institute of Technology (MIT). He wants more imaginative investment to produce radical improvements.

A couple of years ago BMW, which is leading the way with battery-only i3 and i8 plug-in hybrid vehicles, said within four to five years electric cars will have twice the current power and double the range.  BMW board member Ian Robertson added then, that in the next three to four years there will be more progress in battery development than in the previous 100 years.

Not much sign of that and time is running out.

Given that the current range of battery-electric cars like Nissan of Japan's Leaf is currently only about 75 miles on a good day and it costs about twice as much as a similar sized conventional car, sales prospects of these cars have been cut back sharply from initial claims. Nissan of Japan affiliate Renault of France quietly dropped its early prediction that global electric car sales will reach 10 per cent by 2020. Last week Nissan, apparently exasperated with progress, said it was considering switching its battery suppler to LG Chem of South Korea, from the venture with Japan's NEC Corp.