Tesla's domination of the electric vehicle market is "unsustainable" and will soon be disrupted by start-up Rivian, Morgan Stanley analyst Adam Jonas said Monday.

Jonas, whose thoughts on electric autos are widely followed on Wall Street, expects Rivian will be "the next serious competition from a 'clean sheet' start-up with access to talent & capital focused on the fastest growing segments of pickup trucks & SUVs." He estimates that Tesla makes about 80 percent of the U.S. EV market, capturing as much as 90 percent of U.S. electric vehicle revenues.

Rivian, based outside Detroit, previewed its R1T electric truck prototype at the Los Angeles Auto Show in November. Rivian said the R1T will deliver 400 miles of range, with four individual motors allowing for all-wheel-drive. Additionally, Rivian CEO R.C. Scaringe said the R1T will be able to hit 60 mph in 3 seconds and tow up to 11,000 pounds.