Atomistic computer simulation of oxygen ion conduction mechanisms in La2NiO4

Atomistic computer simulation has been used to predict the most energetically favourable migration pathways for oxygen ion transport in tetragonal La2NiO4. Both interstitial and vacancy mechanisms have been investigated. All of the vacancy mechanisms studied exhibited lower activation energies than the interstitial process. The lowest energy process allowed migration in the a–b plane with an activation energy of 0.35 eV, migration along the c-axis was predicted to have an activation energy of 0.77 eV and interstitial migration in the a–b plane was found to have an energy barrier of 0.86 eV (in agreement with available experimental data).