Richard Musgrove
After decades, Lithium Nickel Oxide (LiNiO2) battery problems may have been solved. Degradation on repeated recharging has meant that these batteries, which offer higher energy density, and could replace expensive and hard-to-source cobalt, have never made it to commercialisation.
Researchers at the University of Texas may have a solution.
Much of your life is powered by lithium ions — stored electricity flowing from your rechargeable batteries, running your world’s devices.
The first commercial lithium-ion battery was launched in 1991, with typically included metals such as cobalt, manganese or iron.
Research on other variants has included lithium nickel oxide (LiNiO2), which offers higher energy density, and could replace expensive and hard-to-source cobalt. But commercialisation has lagged because of degradation after repeated charging, says Dr. Kyeongjae Cho, Professor of Materials Science and Engineering at University of Texas at Dallas (UTD).
Until now.
UTD researchers working in the university’s BEACONS (Batteries and Energy to Advance Commercialisation and National Security) Initiative have worked it out.
When you charge your lithium-ion battery, electrical current flows from the cathode, a positive electrode, through a fluid electrolyte, into the anode, a negative electrode. Anodes are typically graphite (think: pencil lead), which holds lithium ions at a higher potential — lithium ions are positive, so it has taken energy to store them in the negative electrode. Like pushing a kayak upstream. When your phone is on, lithium ions return to the cathode through the electrolyte, generating electricity, so you can make that call.
UTD researchers analysed the chemical reactions and the movement of electrons using a computer model, finding a chemical reaction involving oxygen atoms was causing the LiNiO2 in the cathode to crack.
Their solution?
Make stronger cathodes. Their models showed that positively-charged ions could be used to create ‘pillars’ within the cathodes to increase strength. Theoretically, at least. PhD student, Matthew Bergschneider, lead author in the study, is now making prototypes of the strengthened LiNiO2 cathodes using a robotics-based laboratory to test the theory.
“We’ll make a small amount at first and refine the process,” said Bergschneider. “Then, we will scale up the material synthesis and manufacture hundreds of batteries per week at the BEACONS facility. These are all stepping stones to commercialisation.”
The paper is published in Advanced Energy Materials
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