Toyota will slash the price and size of its hybrid system by around half for the next-generation Prius model, and use a nickel-metal hydride battery instead of lithium-ion, Executive Vice President Kazuo Okamoto, in charge of Toyota's research and development, told reporters in Tokyo.

"I can't tell you when it will come to market, but the preparations are making steady progress," Okamoto said. He added that the next Prius would "definitely" use improved nickel-hydride batteries rather than higher-energy lithium-ion.

"Lithium-ion is going to take some time," he said. reuters