Leading the charge

Representation of silicon (grey) bonding with lithium ions (pink). Image: Northwestern

Lithium-ion batteries have dominated the renewable energy landscape for decades. Could there be a potential successor (or successors) on the way? Ewen Hosie reports.

The lithium-ion (Li-ion) battery has of late returned to a topical forefront.

While this stalwart battery has been around since the early 1980s, an impending tech boom, compounding a long-predicted but still not quite there breakout of commercial electric vehicles with a renewables-led response to the needs of a rapidly changing energy century, has returned the technology to prominence in the public eye.

As global demand for the battery increases, so too does the demand for the tech metals used in its creation; metals such as vanadium, lithium and cobalt are expected to explode in 2018 as industrial production increases.

It is a situation that could prove potentially lucrative for the Australian mining industry. Australia already mines most the world’s lithium (41.5 per cent, comfortably ahead of runner-up Chile’s 35.7 per cent), and had an exceptional 2017.

Companies such as Galaxy Resources, Mineral Resources (MinRes), Orocobre all saw great market capitalisation gains between 50 and 60 per cent over the 2017 financial year, and all saw great profits, particularly MinRes; its posted profit of $201 million was 83 per cent greater than in the 2016 financial year.

And from great profits to great prophets, lithium soothsayers are not lacking in abundance.

Last year noted metallurgist, geologist and Lithium Australia chief executive officer Adrian Griffin referred to this newfound energy opportunity as one of the biggest since the advent of steam. “What you are looking at here is not the lithium industry per se,” he commented last year.

“What you are looking at is the biggest change in energy management since the Industrial Revolution.

“There is insatiable demand because people want portable power and they want renewable energy 24 hours a day. If you want renewables 24 hours a day you have got to have storage.”

Since the recovery of such metals becomes more costly as scarcity has increased, prescient scientists and technicians are turning to research projects focused on battery alternatives that could in future prove more plentiful and cost-efficient than the current crop.

Chris Johnson, a senior chemist and group leader at Argonne National Laboratory (hereafter Argonne), is one such figure; deeply invested in battery research at the renowned Chicagoan research facility, borne from the fruits of the Manhattan project, he is currently involved with two high profile, collaborative projects; Li-ion composites and solid-state magnesium batteries.

The former of these is designed to provide insight into the potential of iron oxide composites as components in rechargeable batteries.

By developing a way to use lithium iron oxide as an additive in Li-ion battery electrodes that use silicon as one of the electrodes, Argonne could potentially develop a roadmap to a cheaper and more efficient production process.

Iron ore is roughly a hundredth of the cost of cobalt, so potential cost savings are extensive. The prospect has attracted some high-profile support.

“Silicon is currently a battery material that is on the roadmap towards advanced Li-ion batteries with higher energy densities,” Johnson told Australian Mining. “We have had support from the US Department of Energy for about three years to develop this lithium-iron oxide technology.

“As a transition metal, in principle, it could function as a positive electrode material in Li-ion batteries.”

There is a notable downside, however, and that lies in performance, which does not match up to cobalt currently, and researchers worldwide, including Johnson and his colleagues at Argonne, are still exploring new ways to integrate and synthesize lithium-iron oxides for batteries.

The project is not to be confused with lithium-iron phosphate (or LiFePO4) batteries, which already exist commercially. While these batteries are generally safer and longer lasting than cobalt-based Li-Ion batteries, they still rely on carbon coating for conductivity purposes, a process lithium-iron oxide batteries can bypass.

“While LiFePO4 batteries contain iron, as do lithium-iron oxides, the chemistries are quite different,” Johnson explained.

“The phosphate material is made under inert gas, and lithium iron oxides can be synthesised in either gas environments, depending on what phase is desired; as a battery material LiFePO4 undergoes two-phase electrochemical reaction, while lithium-iron oxide is single-phase intercalation.”

Argonne’s second major battery research project at the moment involves the study of solid-state magnesium batteries, a technology Johnson admits is still in its early infancy, lacking in easily identifiable commercial applications and market abilities.

Magnesium batteries are pretty much still a lab curiosity right now,” he said. “If they do become feasible, then in principle they have a higher volumetric energy density than Li-ion batteries.

“A solid-state electrolyte would have the advantage of being more intrinsically safe as compared to conventional liquid containing flammable electrolyte in Li-ion batteries; considering that lithium-iron oxides are potentially very low cost and the growth of Li-ion batteries is really large, the adoption of this technology is possible.

“But performance needs to be improved, so a commercial release is likely far from realisation.”

Going forward, the trend in battery materials for 2018 and beyond will still focus largely on battery chemistry, moving away from cobalt systems to manganese and nickel systems. Silicon, too, should remain a choice material to use in electrodes, according to Johnson, on account of its low cost, high capacity, and high energy densities.

“The rechargeable battery industry is under extreme growth right now. Moving to a renewable energy portfolio with electric vehicles powered from non-carbon energy sources is the future vision,” he explained.

“To make that happen will require many players in the industry, working hard and efficiently towards that goal. Economically, rechargeable batteries show a tremendous market growth chart, and the lithium-ion battery chemistries will continue to dominate for years to come.”

Whether or not a more efficient successor to the lithium-ion battery is ever found, the Australian mining industry should be in a strong position to meet the demands of any requisite changes. Western Australia is the world’s largest iron exporter and producer, Australia holds estimated production of 440,000 tonnes per year (eighth in the world), and is the number one producer of high-grade irradiate silicon.

Whatever we end up using to keep the lights on, the future looks bright for battery production.

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