Sodium‐Ion Batteries: Understanding the Capacity Fading Mechanisms of O3‐Type Na[Ni0.5Mn0.5]O2 Cathode for Sodium‐Ion Batteries (Adv. Energy Mater. 37/2020)

In article number 2001609, Yang-Kook Sun and co-workers explore the capacity fading mechanisms of O3-type Na[Ni0.5Mn0.5]O2 cathodes for sodium-ion batteries. A phase transition at a largely desodiated state compromises the mechanical integrity, and a sudden collapse during the phase transition leads to microcrack formation and fracture of the secondary particles. Microcracks traversing the entire secondary particle cause internal degradation of the exposed internal surfaces.