The agreement covers 17,500t per annum of AAM for three years, with Tesla having option to increase up to 35,000tpa.
As is typical, no details on pricing were released.
Magnis now needs to find a production site and build an AAM plant, as well as build a graphite mine at its Nachu deposit in Tanzania.
The multi-faceted Magnis also owns about 10% of battery technology company C4V and has about 61% of iM3NY, a "gigawatt scale battery manufacturing facility" in New York.
The Frank Poullas-led Magnis had cash at the end of December of A$44.5 million.
Shares in Magnis were up 10% to 44.5c in morning trade, capitalising the company at $432 million.
The stock is little changed from levels 12 months ago.
