Japan has developed a cobalt and nickel-free battery with an incredibly high energy density of 820 Wh/kg. The key is a new material based on lithium manganese oxide.
The issue with lithium batteries. Lithium batteries power almost all of our electronics, as well as our electric cars and energy storage systems.
However, for these larger-scale applications, they have two main drawbacks: their low energy density, leading to larger and heavier battery packs, and the high cost and environmental impact of some of their components, particularly cobalt.
A Ni/Co-free battery. Nickel and cobalt are used to make the cathode, one of the electrodes responsible for the electrochemical reaction that charges and discharges batteries. Nickel increases capacity and energy density, while cobalt improves thermal stability, helping the battery maintain its capacity for longer periods.
Cobalt is the most expensive metal in a lithium battery, even more so than lithium itself. Its high cost is due to its limited geographical availability: 70% is mined in the Democratic Republic of Congo, where political instability has led to fluctuating production levels.
Some of DRC mines are also criticized for their inhumane conditions and child exploitation. This has spurred interest in developing a battery that doesn’t require cobalt or its associated metal, nickel.
Japan’s breakthrough. A team of researchers at Yokohama National University has developed a promising alternative to the common nickel-cobalt batteries. They started with LiMnO2 batteries, which use lithium oxide and manganese in their electrodes, but offer much lower performance.
After studying LiMnO2 in various forms using X-ray diffraction, scanning electron microscopy and electrochemical methods, the researchers created a nanostructured version with significantly better performance and three times the energy density.
Energy density of 820 Wh/kg with no voltage drop. Unlike other similar materials, the battery didn’t suffer significant voltage drop with charge/discharge cycles. The new material retained 75% of its 820 Wh/kg capacity even with a very high charge rate.
The key was developing a mixed crystalline structure, known as a monoclinic lattice, and addressing practical problems, such as manganese dissolution, by coating the material with lithium phosphate and using a highly concentrated electrolyte.
Much cheaper to produce. The main thing is this material can be synthesized using a simple and inexpensive method. This breakthrough could lead to the production of high-performance batteries without the need for scarce and expensive metals like nickel and cobalt.
The Japanese researchers are confident that their work will contribute to the development of a new technology that isn’t only competitive with existing options but also sustainable and environmentally friendly.
Image | CHUTTERSNAP (via Unsplash)
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