Nanotechnology

Organic chemistry

Cracking

Crystallography

Computer graphics (images)

Engineering

Agglomerate

Planar

Crystallite

Physical chemistry

Chemical physics

Composite material

Chemistry

Materials science

Computer science

Cathode

Chemical engineering

Oxygen

Journal of the American Chemical Society

Single-crystalline Ni-rich cathodes with high capacity have drawn much attention for mitigating cycling and safety crisis of their polycrystalline analogues. However, planar gliding and intragranular cracking tend to occur in single crystals with cycling, which undermine cathode integrity and therefore cause capacity degradation. Herein, we intensively investigate the origin and evolution of the gliding phenomenon in single-crystalline Ni-rich cathodes. Discrete or continuous gliding forms are revealed with new surface exposure including the gliding plane (003) and reconstructed (-108) under surface energy drive. It is also demonstrated that the gliding process is the in-plane migration of transition metal ions, and reducing oxygen vacancies will increase the migration energy barrier by which gliding and microcracking can be restrained. The designed cathode with less oxygen deficiency exhibits outstanding cycling performance with an 80.8% capacity retention after 1000 cycles in pouch cells. Our findings provide an insight into the relationship between defect control and chemomechanical properties of single-crystalline Ni-rich cathodes.

<b>Kinetic Origin of Planar Gliding in Single-Crystalline Ni-Rich Cathodes</b>