Toyota is making the Prius hybrid more efficient than ever with a diamond-like chip that will carry electricity through the car’s drivetrain without losing energy. Toyota says the new technology could boost the car's fuel efficiency as much as 10 percent.

The trick is a new semiconductor made of silicon carbide, which is smaller, tougher, and more efficient than the current technology.

Scientists have been making silicon carbide, the synthetic version of the extremely rare mineral moissanite, since the 19th century. Along with diamonds, it is among the world's hardest materials. It is used in body armor and carbon ceramic brakes, among other things. (It also stands in for diamonds in cheap engagement rings, though that's less useful here.)

As it turns out, silicon carbide also is a semiconductor well suited to high-temperature or high-voltage devices like, say, electric and hybrid vehicles. Toyota currently uses silicon semiconductors within the car's power control unit to manage the flow of electricity from the battery to the motor to control vehicle speed; they also manage the flow of energy from the brakes to the battery. The PCU isn't terribly efficient, though – the semiconductors alone suck up about 20 percent of the juice. Toyota says it has been quietly working since 1997, the year it introduced the Prius, to alleviate these losses. It has settled on using silicon carbide in semiconductor it claims will boost efficiency by 10 percent while reducing the size of the power control unit by 80 percent. Toyota’s current units can be twice the size of a shoe box.

Toyota says the semiconductors will offer “superior characteristics such as one-tenth the electrical power loss and ten times the drive frequency.” Translated into terms that mean something to consumers, that's a 5 to 10 percent percent bump in fuel economy. Toyota claims it's already seen a 5 percent bump during testing on its road course. That's not huge, but it will add up over time. The 2014 Prius is EPA-rated for 50 mpg.

Toyota plans to begin road-testing the technology in Japan later this year, but says we won't see it in showrooms until 2020 at the earliest.