The August issue of The Canadian Journal of Chemical Engineering is marking a research initiative dedicated to improving the commercial prospects of lithium battery storage. This special issue section showcases efforts in Canada to develop melt synthesis and manufacturing processes for lithium iron phosphate (LiFePO4 or LFP) as a cost-effective alternative to conventional battery cathode materials.
LiFePO4 has been extensively studied, but the authors of the preface begin with an important distinction: of some 6,200 articles on LFP that have been published since 1997, only 250 were in journals designated as chemical engineering. At the same time, they point to more than 4,300 patents that have been filed with respect to some aspect of LFP battery production, which makes it all the more striking that Canadian researchers have been able to bring something new and promising to this field.
“This is about engineering as opposed to chemistry,” explains Gregory Patience, MCIC, a member of the Department of Chemical Engineering at Montreal’s École Polytechnique who has led much of this work. “It’s a matter of the implementation of innovation, rather than pure discovery.”
He is referring to a 2005 breakthrough by a Université de Montréal team that found LFP to be stable in a molten state at temperatures in excess of 1000ºC, well above the point required for solid state integration of this material into a battery cathode. Since then, these investigators have been joined by colleagues from École Polytechnique de Montréal, Western University, and the multinational firm Johnson Matthey Battery Materials to determine how this process could be scaled up to commercial levels.
Their work has been funded by Automotive Partnership Canada, an industry-led funding stream intended to accelerate the entry of new technologies into the design and manufacture of vehicles. In this case the motivation was the market viability of electric and hybrid vehicles, which has been determined in part by the cost of rechargeable batteries. While the current generation of lithium ion cells has demonstrated the technical viability of this form of energy storage, the cost of key battery constituents like cobalt and nickel has added significantly to the selling price of these vehicles, which account for only a tiny fraction of the world’s automotive fleets.
LFP represents a far less expensive alternative to these battery materials, one that could be obtained reliably from domestic suppliers rather than less predictable international sources. According to Patience, a scaled-up process should be possible at a price point that would eclipse that of the current generation of batteries.
“Iron can be obtained for as little as 10 cents a kilogram, versus as much as $20 for a kilogram of cobalt,” he says, adding that this lower cost makes it easier to accommodate a complete life cycle expenses associated with battery manufacture. When prices are high, it becomes more tempting for firms to minimize factors such as environmental stewardship and safety.
In fact, LFP is inherently safer from an operating perspective, says Pierre Sauriol, a process engineer who has overseen most of this research. “There’s no risk of oxygen being released when it’s heated up, as opposed to most of the other materials,” he says.
Sauriol acknowledges that the performance of LFP batteries does not match that of their cobalt-nickel counterparts, but their lower cost could nevertheless mean they will achieve much greater adoption. Patience echoes that perspective, noting that the currently minuscule uptake of battery-powered vehicles illustrates the crucial role of price in the marketplace.