Dreaming of a future wherein humanity has begged off fossil fuels entirely in favor of completely electrical systems for fuel is a tantalizing activity. But, much like the rest of science, the concept requires work and time to achieve—and much work and time our experts do impart to it on a daily basis, just to see it come to fruition.
Part of the obstacles that lie ahead of electric vehicles (EVs) is the fact that current battery technologies just can’t seem to reach the full potential made possible by fossil fuel-driven engines. In particular, the rapid pace of vehicular travel means that drivers can’t simply stay in one spot for hours at a time just to charge their EV’s batteries, much unlike fossil fuel-based cars of yesteryear that simply gas up at their nearest fuel pump then proceed to travel again.
One solution that addresses this is the use of fast-charging technologies; however, the fast charging that’s already made available in mobile phones aren’t necessarily compatible for use in EVs, too.
You see, common rechargeable battery technologies make use of a standard setup, wherein two battery electrodes—one positive cathode, and one negative anode—are separated by a liquid electrolyte, which allow for the transfer of ions from one side to the other. (Read further on how usual battery technologies work with our previous pieces on chlorine-based rechargeable batteries.)
Thing is, some smartphones achieve fast charging on these kinds of batteries by deploying two of them at once in a single phone, and allowing them to charge and discharge in parallel; this method is quite unfeasible in EVs, as every kilogram of weight you can shave off the car is a kilogram more that the driver and passengers can carry with them—and batteries are pretty heavy.
Another issue to address is the fact that batteries with liquid electrolytes pose more than just excess baggage for the car; they also pose a hazard, as the chemicals present in electrolytes are often dangerous to humans, whether by exposure or by reactivity.
Luckily for scientists and engineers, there’s a way out of the fast-charging tunnel for EVs; solid-state batteries, or batteries wherein all the components are solid, electrolyte included. This skips the dangerous chemicals used by normal rechargeable batteries. These all-solid batteries were actually already discovered close to two (2) centuries ago; however, limitations in energy density—or the amount of energy that can be stored per given volume—rendered the practically old technology unusable for decades. It was only due to the recent advancements in battery research that made even the concept of using solid-state batteries close to viable.
And, much like how previously-reported research reports the possibility of using lithium-sulfur batteries for liquid electrolyte-based technology, researchers from Oak Ridge National Laboratory (ORNL) are hard at work closing the gap between solid-state batteries and the rest of the works out there. Truth be told, they’re also literally closing the gap between parts of solid-state batteries with what they found, which was published in the journal ACS Energy Letters.
ORNL researchers enabled the use of electrochemical pulses that are designed to close pores that are otherwise present in contacting surfaces between solid electrolytes and solid electrodes. In ORNL’s case, their solid electrode makes use of solid lithium (Li) metal, which while recognized as a potential candidate for the future of solid-state batteries due to its high energy density.
Applying the electrochemical pulses through the battery reverts electrical currents to pass around the pore, restoring pores and improving the contact between electrode and electrolyte. In doing so, the pulsing reverts internal battery damage brought about by the charge-discharge process by removing voids inside the contact surfaces, preventing the buildup of contact impedance.
The pulses don’t appear to be destructive, and cause no damage to the battery itself—meaning the process doesn’t compromise performance, according to the ORNL researchers. This gives a tantalizing opportunity to create damage mitigation technologies for the potential future of EV batteries.
Said co-lead author and head of ORNL’s Electrification Section Ilias Belharouak: “This method will enable an all-solid-state architecture without applying an extrinsic force that can damage the cell and is not practical to deploy during the battery’s usage. In the process we’ve developed, the battery can be manufactured as normal and then a pulse can be applied to rejuvenate and refresh the interface if the battery becomes fatigued.”
References
- Lavars, N. (2021, November 11). Electrochemical pulses address weakness in next-gen lithium metal batteries. New Atlas. https://newatlas.com/energy/electrochemical-pulses-voids-lithium-metal-battery/
- Oak Ridge National Laboratory. (2021, November 10). New scalable method resolves materials joining in solid-state batteries. Oak Ridge National Laboratory. https://www.ornl.gov/news/new-scalable-method-resolves-materials-joining-solid-state-batteries
- Parejiya, A., Amin, R., Dixit, M. B., Essehli, R., Jafta, C. J., Wood, D. L., & Belharouak, I. (2021). Improving contact impedance via electrochemical pulses applied to lithium–solid electrolyte interface in solid-state batteries. ACS Energy Letters, 6(10), 3669–3675. https://doi.org/10.1021/acsenergylett.1c01573
