Dislocation and oxygen-release driven delithiation in Li<sub>2</sub>MnO<sub>3</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32901015.
- Also identified by DOI 10.1038/s41467-020-18285-z and PMC identifier 7479600.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Lithium-excess layered cathode materials such as Li<sub>2</sub>MnO<sub>3</sub> have attracted much attention owing to their high energy densities. It has been proposed that oxygen-release and cation-mixing might be induced by delithiation. However, it is still unclear as to how the delithiated-region grows. Here, by using atomic-resolution scanning transmission electron microscopy combined with electron energy-loss spectroscopy, we directly observe the atomic structures at the interface between pristine and delithiated regions in the partially delithiated Li<sub>2</sub>MnO<sub>3</sub> single crystal. We elucidate that the delithiated regions have extensive amounts of irreversible defects such as oxygen-release and Mn/Li cation-mixing. At the interface, a partially cation disordered structure is formed, where Mn migration occurred only in the specific Mn/Li layers. Besides, a number of dislocations are formed at the interface to compensate the lattice mismatch between the pristine and delithiated regions. The observed oxygen-release and dislocations could govern the growth of delithiated-regions and performance degradation in Li<sub>2</sub>MnO<sub>3</sub>.