Are we really ready to make a complete turn to electric vehicles in the coming decades? If we know well the social and geopolitical challenges associated with the materials contained in the batteries, few people have looked into electrolytes, while the European Parliament as several countries want all the new vehicles sold to be electric within 10 years.
The professor of the Department of Chemistry of the University of Montreal Olivier Fontaine and colleagues have immersed themselves in this reflection. “We have asked ourselves the question of the reality of this approach: with current technology, is it a political announcement or the production chain follow?” Our conclusion is rather alarming: we don’t really have a viable solution, ”he says. Their reflection has just appeared in the review Nature Communications.
Electrolyte, the poor parent of research and innovation
Olivier Fontaine
Credit: Amélie Philibert, University of Montreal
A battery has three compartments: a positive electrode, a negative electrode and, in the center, electrolyte. “This is what separates the two electrodes and allows the ions to circulate and operate the battery without it exploding,” explains Olivier Fontaine.
Several research teams and companies have set out to find greener, more efficient or more local materials for the manufacture of electrodes. But for the electrolyte, almost nothing has been done. “We often consider that it is easy to produce because it is a salt that we mix with a solvent. The companies buy liquid electrolytes from China, but it’s a bit of a black box, there is almost no questions, “he said.
However, to make these electrolytes, we will need mining resources: phosphate, lithium and fluoride. Many resources. “This will generate other geopolitical problems because these resources are not abundant in all countries,” raises Olivier Fontaine.
Scenarios
To expand their reflection, the team has envisaged three scenarios to estimate the needs in electrolyte (and therefore minerals) of each country: the first simulates complete electrification of the car fleet and the other two are based on predictions of adoption rate of electric vehicles. Olivier Fontaine and his colleagues then examined the geographic distribution of these critical minerals.
With the planned scaling, it is up to 1.5 million tonnes of electrolytes that would be necessary. “Imagine that we will be able to make an energy transition with 100 % electric cars is going straight into the wall, at least with current technology,” summarizes the researcher.
Indeed, to be effective, the batteries are notably powered by hexafluorophosphate of lithium, a fluorinated salt based on lithium and phosphate. On the one hand, phosphate is used in a host of areas, among other things in agriculture as fertilizer. “From the moment when phosphates are used to roll a car, these are phosphates that are not used to make fertilizers or other types of technologies,” he notes. This is without counting that almost 50 % of phosphate reserves are in a single country, is Morocco, which is announcing tensions in the supply chain. “We want energy independence so that we no longer have a problem of geopolitics with oil, but that creates others,” he adds.
Major changes to consider
The authors also examined spare solutions, either recycling, greener electrolytes or new materials. Thus, some components could be produced with biomass. But as with biofuels, these supposedly green solutions have the great disadvantage of monopolizing agricultural land to roll vehicles rather than to feed humans. In addition, these ways from biomass produce electrolytes containing water. However, “lithium batteries work very well today because the electrolyte is non -aqueous. If using an aqueous electrolyte, the battery voltage is very reduced. The slightly greener tracks contain water by default; It weighs down all the innovation, ”he says.
The recycling of electrolyte in the end of life batteries is another avenue to consider, even if for the moment it is also paved with difficulties. Most recycling processes are currently only interested in electrodes materials, completely ignoring electrolyte – whose variable composition makes its recovery difficult.
The scientific community will therefore have to accelerate the search for sustainable spare solutions to electrolytes, to which the researcher and his colleagues are tackling. And despite everything, “to imagine that, in 10 years, there is a spare solution to electrolyte, it’s illusory,” he believes. Because these new materials must be economical, green, abundant, effective and stable, and their development will take several years. “Faced with elements that are multidimensional, artificial intelligence could help answer these questions,” he hopes.
But the company will also have to see its relation to the car, suggests Olivier Fontaine. “We see the electric car as the continuity of the thermal car, but there may be another model to imagine. The greener electrolytes are less efficient, but if we change our consumption habits of the car, they could have a role to play in the transition, “he concludes.
