Changing the Oxygen Composition of Lithium-Rich Cathode Material Could Improve Battery Life, New Study Shows

A new study revealed that changing the oxygen composition of lithium-rich cathode materials could improve battery performance.

The study, published in the journal Nature Communications, suggests that creating oxygen vacancies at the surface of lithium-rich cathode materials using a carbon-based gas mixture can increase the robustness and energy storage capacity of the material.

Lithium-rich layered oxide, a class of cathode materials, is currently becoming popular among battery researchers due to its potential in housing more energy than other cathode materials. However, lithium-rich cathode materials have some drawbacks, including slow discharge rates and an issue called voltage fade, which is characterized by a drop in cell voltage with each charge-discharge cycle.

"We're presenting a new way to mitigate the issues plaguing lithium-rich cathode materials -- through understanding and controlling how oxygen behaves in these materials," explained Shirley Meng, nanoengineering professor at the University of California San Diego and one of the principal investigators of the study, in a statement. "Now we're showing that oxygen also plays a significant role in battery performance."

For the study, the researchers treated the lithium-rich cathode particles with a carbon dioxide-based gas mixture, creating oxygen vacancies uniformly throughout the surface of the particles. The treatment only left oxygen vacancies within the first 10 to 20 nanometers without altering the rest of the material's atomic structure.

The researchers then tested the treated lithium-rich cathode using electrochemical test. The researchers noted that the treated material was able to exhibit relatively high discharge capacity, about 300 milliamp-hours per gram, with only minor voltage loss after 100 charge-discharge process.

According to a press release, the researchers believe that the oxygen vacancies created by the carbon-based gas mixture allowed lithium ions, which led to the high discharge capacity and faster discharge rates. Additionally, the oxygen vacancies inhibited the formation of highly reactive oxygen radicals at the cathode material's surface, increasing the material's stability.

The researchers are planning to take their findings to the next level, scaling up the treatment they previously used and conducting further studies on the oxygen activity in other materials and how it could be leveraged to improve battery performance.