Based upon the Heyd–Scuseria–Ernzerhof hybrid density functionals study, a new insight into the diffusion of polaron–Li vacancy complexes in LiFe1-yMnyPO4 (y = 0,1/2,1) was proposed. It was found that the polaron migrates along a crossing or a parallel path relative to the Li moving direction. In LiFePO4, the complex diffusion along the zig-zag pathway was favorable and has a barrier of 600meV, while the diffusion along the parallel pathway with a barrier of 623meV was favorable in LiMnPO4. For LiFe1/2Mn1/2PO4, since the polaron was formed within a single Fe layer, the diffusion proceeds along the parallel pathway with a barrier of 635meV.

A New Insight into the Polaron–Li Complex Diffusion in Cathode Material LiFe1-yMnyPO4 for Li Ion Batteries. V.A.Dinh, J.Nara, T.Ohno: Applied Physics Express, 2012, 5[4], 045801