NEW YORK - Global X Funds said Thursday it will unveil on Friday the world's first lithium exchange-traded fund in shares of the largest and most liquid lithium battery producing and mining and refining companies.

"The Global X Lithium ETF is an efficient way to invest in what we refer to as a "green" commodity because of its direct correlation to the renewable energy market such as electric cars and energy storage," said Bruno del Ama, CEO of Global X Funds in a press release.

Lithium is expected to be in increasing demand as carmakers look to costly but more efficient lithium-ion batteries to power hybrid and electric vehicles.

The new lithium ETF will trade under the ticker symbol on the New York Stock Exchange.

It is based on the Solactive Global Lithium Index, which is designed to reflect the performance of the largest and most liquid lithium battery producing and mining and refining companies in the world.

The ETF consists of 20 different companies, with a market capitalization of $29,8-billion.

As of July 13, 51 percent of the index was made up of lithium battery manufacturers, with the rest comprised of lithium mining and refining companies.

The top three holding were lithium producers SQM from Chile, FMC Corp and Rockwood Holdings from the United States.

"Lithium is the lightest metal," said Jose C. Gonzalez, chief operating officer of Global X Funds.

"When processed, it has the capacity to store electric energy more efficiently than any other material. Efficient electric energy storage is necessary for all green energy products and the computer systems that control them -- like electric cars, solar, wind and water power," he said.