The plant under construction outside Reno is expected to be one of the first US facilities to produce key ingredients needed to make the batteries that power electric vehicles, the report said.
The auto industry has been ramping up production of electric vehicles to meet a demand surge, driving up orders for batteries and raw materials that have limited supply.
The report in the Journal said the $3.5 billion would be spent over 10 years and employment at the Nevada plant could reach more than 1,500 full-time jobs in that time.
Redwood Materials did not immediately respond to a Reuters request for comment.
In May, Straubel said his company aimed to start production of copper foil used for electric vehicle battery anodes at its Nevada facility by the end of 2022, adding that Panasonic Corp. would be the first customer for the anodes.