John McCain says 300 million dollars is "a small price to pay for helping to break the back of our oil dependency."
That's the size of a government prize he is proposing for anyone who can develop a car battery that far surpasses existing technology.
The prize would equate to $1 for every man, woman and child in the country.
The presumed Republican presidential nominee announced his idea in a speech at Fresno State University in California.
The Arizona senator also proposed stiffer fines for automakers who skirt existing fuel-efficiency standards, as well as incentives to increase use of domestic and foreign alcohol-based fuels such as ethanol.
He would also offer U.S. automakers a $5,000 tax credit for every zero-carbon emissions car they develop and sell.