Nissan Motor Co.'s Leaf, the first mass-produced electric car sold in the United States, took an early lead in the budding market for rechargeable autos by pulling ahead of General Motors Co.'s plug-in Volt in the first half.

Sales of lithium-ion powered Leafs totaled 3,875 this year through June, buoyed by a record 1,708 units delivered last month, Al Castignetti, Nissan's vice president of U.S. sales, said in an interview Friday. Deliveries of the plug-in Chevrolet Volt, which led the Leaf through May, were 561 in June and totalled 2,745 in the first half, GM said.

"We've been telling you we'd grow every month, and now you're seeing more normalized production flow," Castignetti said. "We're starting to catch up with the reservations."