Researchers from the Stanford Institute for Materials and Energy Research (SIMES) and the Stanford Synchrotron Radiation Lightsource (SSRL) have made a significant stride in understanding the redox mechanism of lithium-ion batteries, which could pave the way for developing high-energy batteries for electric vehicles and other modern energy applications.
The team, led by Dr. Eder G. Lomeli and Dr. Wanli Yang, challenged the conventional understanding of redox processes in lithium-ion batteries. Traditionally, it was believed that redox processes in these batteries occur on cations at low voltages and on anions, specifically oxygen, at high voltages. However, the researchers found that high-energy layered cathodes, such as those made from LiCoO2 and LiNiO2, operate through a mechanism called negative charge transfer (NCT) throughout the entire voltage range. This finding was published in the journal Nature Communications.
The researchers used a combination of in-situ and ex-situ spectroscopy techniques, coupled with theoretical calculations, to observe the NCT process. They found that NCT involves the creation of oxygen holes and high covalency, which leads to optimized battery performance without the need for conventional redox centers. The level of NCT, or the number of ligand holes, can explain many previously controversial results in battery research.
This redefinition of the redox mechanism in lithium-ion batteries provides a new pathway towards developing viable high-energy battery electrodes. The findings could help researchers design new cathode materials that can operate at high voltages without compromising stability, addressing a significant technical bottleneck in the field. This could lead to the development of batteries with higher energy densities, which are crucial for applications such as electric vehicles and grid storage.
The research was published in Nature Communications, a peer-reviewed scientific journal that covers all areas of the natural sciences. The findings represent a significant advancement in the understanding of battery chemistry and could have profound implications for the energy sector.
This article is based on research available at arXiv.