Startup Seeo has developed batteries that store far more energy than conventional ones, which could extend the range of electric cars. An experimental lithium-ion battery based on materials developed at a U.S. Department of Energy lab stores twice as much energy as the batteries used in most electric cars. If the technology can be commercialized, it could give affordable electric cars a range of over 200 miles per charge, says Hal Zarem, CEO of Seeo, a startup that’s working on the technology. Today the cheapest electric cars, which cost around $30,000, typically have a range of less than 100 miles....