A New Insight into the Polaron–Li Complex Diffusion in Cathode Material LiFe1-yMnyPO₄ for Li Ion Batteries

Based on the Heyd–Scuseria–Ernzerhof hybrid density functionals study, we proposed a new insight into the diffusion of polaron–Li vacancy complexes in LiFe 1- y Mn y PO 4 ( y =0,1/2,1). It is found that the polaron migrates along a crossing or a parallel path relative to the Li moving direction. In LiFePO 4 , the complex diffusion along the zigzag pathway is favorable and has a barrier of 600 meV, while the diffusion along the parallel pathway with a barrier of 623 meV is favorable in LiMnPO 4 . For LiFe 1/2 Mn 1/2 PO 4 , since the polaron is formed within a single Fe layer, the diffusion proceeds along the parallel pathway with a barrier of 635 meV.