Li-S Energy (ASX:LIS) obtained regulatory approvals to ship its prototype lithium-sulfur cells by air to the US from Australia, according to a Wednesday filing with the Australian bourse.

The approvals from the Australian Civil Aviation Safety Authority and the US Pipeline and Hazardous Materials Safety Administration pave the way for direct supply to customers in the world's largest defense market, the company said.

Li-S Energy is also pursuing UN38.3 cell certification to enable larger-volume shipments under standard dangerous goods classifications, per the filing.