Facilitating Lithium-Ion Diffusion in Layered Cathode Materials by Introducing Li(+)/Ni(2+) Antisite Defects for High-Rate Li-Ion Batteries

Li(+)/Ni(2+) antisite defects mainly resulting from their similar ionic radii in the layered nickel-rich cathode materials belong to one of cation disordering scenarios. They are commonly considered harmful to the electrochemical properties, so a minimum degree of cation disordering is usually desired. However, this study indicates that LiNi(0.8)Co(0.15)Al(0.05)O(2) as the key material for Tesla batteries possesses the highest rate capability when there is a minor degree (2.3%) of Li(+)/Ni(2+) antisite defects existing in its layered structure. By combining a theoretical calculation, the improvement mechanism is attributed to two effects to decrease the activation barrier for lithium migration: (1) the anchoring of a low fraction of high-valence Ni(2+) ions in the Li slab pushes uphill the nearest Li(+) ions and (2) the same fraction of low-valence Li(+) ions in the Ni slab weakens the repulsive interaction to the Li(+) ions at the saddle point.