The company owns 75% of Cauchari in the joint venture with Australian-based Orocobre, which has the neighbouring Olaroz brine operation.
The PEA by WorleyParsons Chile put Cauchari preproduction capex at $401 million for a 25-year mine life ramping up to a 20,000 tonne per year operation.
It put the after-tax NPV (8% discount) at $827 million and the internal rate of return at 24.3%.
The PEA was based on the May resource update of an inferred 3.02 million tonnes of lithium carbonate equivalent.
It envisaged producing technical grade lithium for the first three years, starting in 2021, and battery grade from year four onwards, ramping up from 20% to 80% of production.
Advantage Lithium has engaged Goldman Sachs & Co to evaluate "strategic partnerships and financing alternatives" to fund its portion of development capital.
"We are very pleased that we have advanced our Cauchari JV from exploration through to a completed PEA in just over a year," founder and CEO David Sidoo said.
"This clearly demonstrates the potential of Cauchari JV as a robust project with operating costs expected to be in the lower quartile of the industry cost curve."
The company is planning to add to its project team and advance rapidly through well testing and drilling to support resource to reserve conversion.
Advantage Lithium raised just over C$12 million (US$9 million) last month at 77c per share for general working capital plus development and exploration at its lithium properties in Argentina.
Its shares closed up more than 9.8% yesterday to 89c, near the middle of its 52-week range of 37-$1.42.