PARIS, Nov 13 (Reuters) - Eramet will go ahead with plans to add more capacity in Argentina for the battery mineral lithium and aims to double nickel mine output in Indonesia, in an investment push it sees withstanding a faltering global economy.

The French mining group forecast on Monday capital expenditure of about 1.9 billion euros ($2.03 billion) over 2024-2026, an acceleration in annual investment from 550 million euros expected this year.

"These investments are being made in areas with very high growth," Christel Bories, Eramet's chair and CEO, told Reuters. "Lithium is not tied to world economic growth, it's tied to the development of batteries and the energy transition."

The group said it had approved a second phase for its Centenario lithium project in Argentina to produce about another 30,000 metric tons annually of lithium carbonate equivalent (LCE), on top of the 24,000 tons targeted in a first tranche that will enter production in the second quarter of 2024.

As well as studying a possible third tranche at Centenario, the firm is exploring the nearby Arizaro deposit, Bories said before Eramet's first capital markets day.

Eramet is developing Centenario with Chinese steel giant Tsingshan. A $400 million deal with Glencore

to market lithium

from the project's first stage will mostly cover Eramet's financing needs for the next tranche, Bories said.

In Chile, meanwhile, the group announced it had acquired for an initial $95 million a 120,000-hectare lithium concession in the Atacama region.

Eramet wants to bring output at Weda Bay in Indonesia, the world's largest nickel mine that it also operates with Tsingshan, to 60 million wet metric tons in 2026 from 30 million anticipated this year. (Reporting by Gus Trompiz, Editing by Charlotte Van Campenhout and Louise Heavens)