Microscopic simulations were made of the collective dynamics of Li+ and charge-compensating electron-polarons (e-) in rutile nanoparticles in contact with an idealized conductive matrix and electrolyte. Kinetic Monte Carlo simulations were used, parameterized by molecular-dynamics based predictions of activation energy barriers for Li+ and e- diffusion. Simulations revealed the central role of electrostatic coupling between Li+ and e- in their collective drift diffusion at the nanoscale. They also demonstrated that a high contact area between the conductive matrix and rutile nanoparticles led to undesirable coupling-induced surface saturation effects during Li+ insertion, which limited the overall capacity and conductivity of the material. These results helped to provide guidelines for the design of nanostructured electrode materials having improved electrochemical performance.

Kinetic Monte Carlo Study of Ambipolar Lithium Ion and Electron-Polaron Diffusion into Nanostructured TiO2. J.Yu, M.L.Sushko, S.Kerisit, K.M.Rosso, J.Liu: Journal of Physical Chemistry Letters, 2012, 3[15], 2076-81