New insight into Li/Ni disorder in layered cathode materials for lithium ion batteries: a joint study of neutron diffraction, electrochemical kinetic analysis and first-principles calculations†
Although layered cathode materials LiNixMnyCo1−x−yO2 have attracted much attention due to their number of advantages, the issue of Li/Ni disorder seriously restricts their electrochemical properties. It is very important and pivotal for the better optimization of layered cathode materials to clearly explain the detailed relationships among the Li/Ni disorder, Li+ migration resistance, electrochemical kinetics and electrochemical properties. Here we focus on the LiNixMnyCo1−x−yO2 cathode material and report relationships among the crystal structures, Li+ migration resistance, electrochemical kinetics and electrochemical properties by combining neutron diffraction techniques, electrochemical kinetic analysis techniques and first-principles calculation methods. The results suggest that more Li+/Ni2+ ion exchange will shrink the inter-slab space thickness, causing a higher Li+ ion migration barrier and inferior electrochemical kinetics, all of which should be responsible for the limited electrochemical properties.