Mineral explorer sees tellurium as solid-state clean energy solution, forms company to advance new tech.

Before its use in thin-film solar panels, tellurium was an obscure semi-metallic element with few commercial uses. Today, this rare metalloid is a rising star of solid-state green energy that is helping to transform sunlight and heat into electricity, as well as a secret ingredient in solid-state lithium batteries with the potential to revolutionize electric vehicles.

First Tellurium Corp., a mineral exploration company that is increasingly looking like a technologies firm, is positioning itself to be the go-to source for all things tellurium.

"We see unlimited opportunities for the growth and uses of tellurium," said First Tellurium President and CEO Tyrone Docherty. "One of our key goals is to position First Tellurium at the forefront of the sector's innovation, particularly around renewable energy and energy efficiency, and therefore drive value in the company."

Toward this goal, First Tellurium has established a new company to research, develop, and commercialize the use of tellurium in thermoelectric generators, solid-state devices that transform heat into clean electricity.

"Thermoelectric applications, whereby heat is converted to electricity, represent the number two use of tellurium worldwide," said Docherty.

Solid-state generator

Whether it be a home computer, a massive data farm, a manufacturing facility, a gas-burning automotive engine, or even a human body, heat is often a byproduct of other industrious processes.

Thermoelectric generators offer a solid-state solution to converting that wasted heat into clean electricity.

These devices, commonly known as TEGs, utilize semiconductor materials able to create a voltage potential that is directly proportional to differences in temperature. So, if these devices were placed on 200-degree pipes in an 80-degree building, the difference in the heat on the pipe side of the TEG and the relatively cool room side of the TEG would build up voltage potential that would be converted into DC electrical current.

Because heat harvesting TEG devices do not have any moving parts, they are silent, last a very long time, and have essentially zero need for maintenance.

Tellurium is an excellent semiconductor being utilized in various materials – such as bismuth telluride – going into thermoelectric generators. This metalloid is among the top candidates for new TEG materials.

The research, development, and commercialization of tellurium-based materials for thermoelectric applications will be the main arena of First Tellurium's yet-to-be-named start-up.

"Tellurium's unique properties make it an ideal material for this process," said Docherty. "Our new venture allows us to take these properties further and pursue potential solutions for some of the world's most pressing problems related to greenhouse gases and fossil fuel dependence."

Sun shines on tellurium

The same unique properties that make tellurium ideal for thermoelectric devices make this metal-like element a great semiconductor for the photovoltaic (PV) solar cells that transform photons from the sun into electricity.

In recent years cadmium-telluride (CdTe) thin-film cells have increased in popularity as a lower-cost, longer-lasting alternative to the silicon-based photovoltaic solar panels that have traditionally dominated commercial and residential solar markets.

U.S.-based First Solar, the world's largest manufacturer of CdTe solar panels, is responsible for the rise in popularity of this thin-film solar technology.

The U.S. Department of Energy is intrigued by this homegrown clean energy technology and is investing $20 million into Cadmium Telluride Accelerator Consortium, which is bringing experts from academia, national laboratories, and the private sector together to further improve this clean energy technology.

"While already enjoying great success in the marketplace, recent scientific developments make it clear that CdTe PV has significantly more potential for dramatically higher module efficiency, lower cost, increased lifetime energy, and more rapid production," said Martin Keller, director at DOE's National Renewable Energy Laboratory.

First Tellurium exploration

The rise in popularity of American-made cadmium-telluride solar panels is creating new demand for tellurium. This element that demonstrates both metallic and non-metallic characteristics, however, is very rare.

"Most rocks contain an average of about 3 parts per billion tellurium, making it rarer than the rare earth elements and eight times less abundant than gold," United States Geological Survey penned in a report on the metalloid.

Despite its scarcity, tellurium is often concentrated in copper, gold, and silver deposits.

About a decade ago, First Solar considered mining its own tellurium from the Klondike gold-silver project about 100 miles northeast of Durango, Colorado. When the company decided to forego its own tellurium mining venture, First Tellurium Corp. picked up this property where samples with as much as 3.3% tellurium, along with 33.7 grams per metric ton gold, and 364.8 g/t silver, were collected.

"The Klondike property has by far the highest tellurium grades in rock samples of the hundreds of prospects and mines we examined in the U.S. and Canada from 2006 to 2011," said John Keller, the previous mineral exploration manager for First Solar and a consultant to First Tellurium. "Some samples at Klondike were an order of magnitude higher in tellurium grade than any others we collected in the U.S. or in Canada."

The most advanced project in First Tellurium's portfolio, however, is Deer Horn.

Located in western BC, Deer Horn hosts 93,000 kilograms of tellurium, 100,000 ounces of gold, and 3.3 million oz of silver in the combined indicated and inferred resource categories, making it the only gold-silver project in North America with an industry-compliant tellurium resource.

Lithium-tellurium batteries

Tellurium derived from Deer Horn is being used for research into the development of solid-state lithium-tellurium batteries being carried out at the University of British Columbia Okanagan.

In 2022, a UBC Okanagan research team published a study that shows adding a dash of tellurium enhanced the lifespan, charging time, safety, and capacity of existing lithium battery technologies.

"All-solid-state, lithium-tellurium batteries enable higher energy output with an improved safety rating inside a smaller form-factor, thereby expanding its possible applications," said Jian Liu, principal research chair in energy storage technologies at UBC Okanagan.

Fenix Advanced Materials, a BC-based company that specializes in ultra-high purity metals for the clean energy sector, is supplying the UBC research team with high-quality tellurium derived from Deer Horn.

"The high purity of the tellurium along with the mineral's overall attributes makes it ideal as a rechargeable battery material," said Liu.

University of British Columbia Okanagan

Quasi-solid-state lithium-tellurium battery cells being tested at UBC Okanagan's Advanced Materials for Energy Storage Lab.

Using this material, the team developed a quasi-solid-state lithium-tellurium test battery with a flexible gel polymer electrolyte that allows lithium ions to move between the lithium anode and the tellurium cathode.

"It's possible that tellurium could have the largest single impact on future battery technology over any other critical mineral," said Docherty. "Its properties are unique, the demand is increasing and America's mandate is to source tellurium at home and become less reliant on China is changing the landscape."

If commercial versions of these lithium-tellurium batteries make their way into EVs, it is highly likely that a bit of the electricity charging them will be generated with tellurium-enabled solar panels or thermoelectric devices.

And First Tellurium is establishing itself as a hybrid mineral exploration and tech company at the vanguard of exploring for new sources and new applications for this rare metalloid.