Toyota Motor Corp., which has made a big bet on hydrogen-powered cars, is looking more isolated as industry rivals double down on plug-in electric vehicles as the dominant technology in the emerging post-fossil fuel era.

Three years ago, Toyota President Akio Toyoda, grandson of company founder Kiichiro Toyoda, unveiled the Mirai, a four-door family sedan powered by hydrogen tanks and fuel-cell technology that emits nothing but heat and water — and none of the gases that contribute to global warming.

However, sales of the $57,500 sedan — available in Japan, California and parts of Europe — have yet to break the 5,000 mark, compared to some 300,000 of Nissan Motor Co.'s battery-electric Leaf.