During his time with the State Department, there was an increasing awareness in the US about the need for domestic supply of critical materials such as lithium for the energy transition. Fannon was also previously managing director of diversified miner, BHP.

"Frank has tremendous knowledge about the new energy economy and the importance of secure, domestic supplies of critical materials like lithium," said Standard Lithium CEO Robert Mintak.

Fannon said Standard Lithium had a proven concept that had the potential to be transformative for the lithium industry and "provides a near-term answer to achieving a sustainable North American clean energy supply chain".

"The company has built a technology platform that can help ramp up domestic lithium supply faster and with greater respect to natural resources and the environment," he said.

In March, the company announced the successful conversion of its Arkansas-produced lithium chloride into 99.985% pure lithium carbonate. The lithium chloride intermediate product is produced by Standard Lithium's industrial-scale LiSTR Direct Lithium Extraction (DLE) plant.

The DLE demonstration plant is being used for proof-of-concept and commercial feasibility studies as the company aims to initially produce 21,000 tonnes per year of lithium carbonate equivalent following a project development estimate to cost US$430 million.

Standard has an agreement with chemical company Lanxess to produce lithium from brine that is a byproduct of existing bromine production facilities run by Lanxess in Arkansas.

Shares in Standard Lithium are trading at C$4.07, valuing the company at C$525 million.