Scientists are unlocking potential ways to reduce the dependence of lithium-ion batteries on rare metals

A group of researchers have demonstrated the feasibility of synthesizing electrode materials for lithium-ion batteries (LIBs) using inexpensive elements. Further analysis, this method may reduce industrial confidence in rare metals such as cobalt and nickel.

Details of their findings were published in the American Chemical Society’s ACS Applied Energy Materials on April 11, 2022.

Rare metals are widely used because they form a suitable crystal structure for the key component of LIB, for cathode materials. In these materials, lithium is easily and reversibly removed / inserted.

Scientists have long been looking for ways to incorporate other inexpensive elements into a glass structure. However, just as a certain amount of salt dissolves in water, the solubility of other elements is limited.

The research team led by Professor Tetsu Ichitsubo of the Institute for Materials Research (IMR) at Tohoku University used a different strategy. The energy gain of the “configuration entropy” – the random state of a material – expanded the solubility of the elements by synthesizing new electrode materials: LiCr1 / 4Mn1 / 4Co1 / 4Ni1 / 4O2 and LiCr1 / 5Mn1 / 5Fe1 / 5Co1 /. 5Ni1 / 5O2. This significantly reduced the use of cobalt and nickel.

“Our approach unlocks the potential of other unused elements and allows us to optimize the multiple properties of the electrodes at the same time thanks to the flexible design of the materials,” says Ichitsubo.

Materials synthesized by the new method can also improve the safety of LIBs. Tomoya Kawaguchi, an assistant professor at IMR and author of the corresponding article, says: “Increasing the entropy of the configuration also theoretically increases the stabilization of the electrode material, contributing to the safety of the entire battery.”

Ichitsubo and his team also clarified the degradation mechanisms that affect the battery cycle with these new materials. This will serve as a guideline for the development of new high-performance materials using a high-entropy strategy.

Although their current cyclicality and capacity do not match those of conventional LIBs, their ability to synthesize new electrode materials opens up more avenues for LIB research.

Materials provided by Tohoku University. Note: Content can be edited by style and length.