Manganese cathodes, path to cheaper and safer lithium-ion batteries?

Rechargeable lithium-ion batteries are increasingly used in devices such as smartphones and laptops, electric vehicles and energy storage systems. But reserves of nickel and cobalt, two chemical elements often used in the cathodes of these batteries, are limited. New research opens up a potential safe and low-cost alternative: manganese, the fifth most abundant metal in the Earth’s crust.

A team led by Han-Ming Hau, from the University of California at Berkeley, United States, as well as the Lawrence Berkeley National Laboratory, dependent on the United States Department of Energy, has proven that manganese can be used effectively in a new and promising material for cathodes, that of the so-called XRD. Previous research suggested that to work well, XRD materials needed to be ground down to nanometer-sized particles in an energy-intensive process. But the new study has found that manganese cathodes can work better with particles whose size is about a thousand times larger than the size they were considered to be in order to do their job.

“There are many ways to generate renewable energy, but the important thing is how to store it,” emphasizes Han-Ming Hau. “By applying our new approach, we can use a material that is both abundant on Earth and low cost, and whose production requires less energy and time than some materials marketed for lithium-ion battery cathodes. The new batteries made in this way can store as much energy as conventional batteries and work just as well.

The researchers used a novel two-day process with not very high temperatures (about 200 degrees Celsius). This contrasts with the existing process for manganese-based XRD materials, which requires more than three weeks of treatment.

The researchers used state-of-the-art electron microscopes to capture atomic-scale images of the manganese material in action. They found that, after applying their process, the material formed a nanoscale structure that guaranteed good battery performance.

The new manufacturing process for manganese-based battery materials allows researchers to use larger particles, here observed by a scanning electron microscope. (Image: Han-Ming Hau/Berkeley Lab/UC Berkeley)

Hau and his colleagues present the technical details of their latest advances with manganese cathodes in the academic journal Nature Nanotechnology, under the title “Earth-abundant Li-ion cathode materials with nanoengineered microstructures.” (Fountain: NCYT by Amazings)