Science has generally told us that potassium-ion batteries won’t work, and that the preferred choice is lithium-ion batteries.
But a new study from Oregon State University challenges that view and suggests that potassium-ion batteries offer many advantages over the lithium-ion option under certain circumstances, and may provide new opportunities for energy storage.
The problem with lithium-ion batteries–used to power cellphones, laptop computers and electric cars, to name a few things–is that there is limited availability of lithium. Potassium, on the other hand, is widely available–1,000 times more abundant than lithium, said Xiulei (David) Ji, the lead author of the study and an assistant professor of chemistry in the College of Science at Oregon State University.
“There’s not enough lithium to power every single electric vehicle and store electric energy,” he said in an interview. While potassium supplies are abundant, people have assumed it wouldn’t work with graphite in a battery.
“We demonstrated that we can have a potassium-ion battery configuration. Potassium is really abundant and is widely available.
“In terms of grid storage, we looked at the chemistry,” he said. “Potassium ions are heavier and bigger and bulkier (than lithium ions) and would work for grid storage or solar, but not as well for electric vehicles,” he said.
The use of potassium-ion batteries in microgrids is promising, he added. In microgrids, the volume and weight of the battery isn’t as important as they are in electric cars.
“The two problems we have to solve are cost and cycling life,” Ji said. Lithium-ion batteries have to be replaced every two years or so. “For grid storage, we want to be able to leave a battery for a decade and make it work,” he said. “We need to work on that.”
It’s also possible that the potassium-ion batteries will charge faster, he added. “How fast the potassium-ion battery charges and discharges is promising,” Ji said. “But right now it’s premature to say how fast it can charge.”
“It’s safe to say that the energy density of a potassium-ion battery may never exceed that of lithium-ion batteries,” Oregon State said in a press release. “But they may provide a long cycling life, a high power density, a lot lower cost, and be ready to take the advantage of the existing manufacturing processes of carbon anode materials.”
The Oregon State researchers are seeking financial support to continue their research and help commercialize the technology.
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