New technology may lead to cheaper cellphone batteries

Researchers have overturned a decades-old scientific dogma and shown that a potassium-ion battery is possible and can act as a cheaper and more sustainable alternative to lithium-ion batteries that are widely used in cellphones and laptops.
Lithium-ion batteries are ubiquitous in devices ranging from cellphones to laptop computers and electric cars. But there may soon be a new type of battery based on materials that are far more abundant and less costly.
Researchers have now shown that it is possible to develop a potassium-ion battery. The last time this possibility was explored was in 1932.
"For decades, people have assumed that potassium couldn't work with graphite or other bulk carbon anodes in a battery. That assumption is incorrect," said lead author Xiulei Ji, assistant professor in the College of Science at Oregon State University in US.

"It's really shocking that no one ever reported on this issue for 83 years," Ji said.
The findings are of considerable importance, researchers said, because they open some new alternatives to batteries that can work with well-established and inexpensive graphite as the anode, or high-energy reservoir of electrons.

Lithium can do that, as the charge carrier whose ions migrate into the graphite and create an electrical current.
Aside from its ability to work well with a carbon anode, however, lithium is quite rare, found in only 0.0017 per cent, by weight, of the Earth's crust.
Because of that it is comparatively expensive, and it is difficult to recycle.

Researchers have yet to duplicate its performance with less costly and more readily available materials, such as sodium, magnesium, or potassium.
"With most products, as you make more of them, the cost goes down. With lithium the reverse may be true in the near future. So we have to find alternatives," Ji said.
That alternative, he said, may be potassium, which is 880 times more abundant in the Earth's crust than lithium.
The new findings show that it can work effectively with graphite or soft carbon in the anode of an electrochemical battery.
Right now, batteries based on this approach do not have performance that equals those of lithium-ion batteries, but improvements in technology should narrow the gap, he said.

"It's safe to say that the energy density of a potassium-ion battery may never exceed that of lithium-ion batteries," he said.
"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," he said.
The study was published in The Journal of the American Chemical Society.