One of the most widespread concerns about electric cars centers around the availability and cost of cobalt.

Cobalt is an element used in lithium-ion batteries to build stability and increase safety.

While the signature element in modern electric-car batteries, lithium, is mined in only a few countries, it is relatively easily accessible, and so far mining companies seem to have kept up with demand.

Tour of Tesla battery gigafactory for invited owners, Reno, Nevada, July 2016

Tour of Tesla battery gigafactory for invited owners, Reno, Nevada, July 2016

In the earliest type of popular automotive lithium-ion batteries, cobalt made up more than a quarter of the active metals.

It is mainly mined as a byproduct of copper and nickel, and the largest supplies are in the Democratic Republic of Congo, where some experts have expressed concern about human rights abuses, exploitation of child labor, and an unstable government.

The first U.S.-based primary cobalt mine is nearing production in Idaho, according to Streetwise Reports.

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Still, Panasonic, the largest maker of lithium-ion batteries, expects cobalt shortages to arise. Prices have tripled in the last two years, according to Streetwise.

That has led Panasonic, which supplies batteries for Tesla and is a partner in the carmaker's Gigafactory battery plant in Nevada, to announce that it is engineering ways to decrease the cobalt content of its batteries. The company says it has set a target eventually to use no cobalt in its batteries. 

“We have already cut down cobalt usage substantially,” Kenji Tamura, who is in charge of Panasonic’s automotive battery business, said at a meeting with analysts, according to Reuters. “We are aiming to achieve zero usage in the near future, and development is underway.”

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Last week, Panasonic said that it had increased the nickel content of its batteries while significantly reducing the cobalt content, maintaining superior thermal stability and "achieving the highest energy density," Reuters reported.

Other types of lithium-ion batteries, including lithium-manganese spinel and lithium nickel cobalt aluminum oxide, use less cobalt, while still other chemistries such as lithium-iron phosphate may not require cobalt. Battery makers are trying to balance the batteries' power output and energy storage against stability, safety, and lifespan as they adjust their chemical balance.

Teams of scientists and venture capitalists from the U.S. and Japan are working to develop solid-state lithium batteries, which would primarily benefits cars and trucks. Ultimately, solid-state lithium batteries may not require cobalt at all, but so far their production processes and costs are unproven.