Distinct configurations of antisite defects in ordered metal phosphates: comparison between LiMnPO4 and LiFePO4.

By using a combination of aberration-corrected high-angle annular dark-field scanning transmission electron microscopy, ab initio density-functional theory calculations, and neutron powder diffraction techniques, We have found completely different configurations of the antisite exchange defects in LiMnPO4 and LiFePO4, with a random distribution of the exchange pairs without aggregation in the former and with zigzag-type clustering behavior preferred in the latter. Recalling the compositional analogy and identical crystal structure of the two metal phosphates, such unexpectedly distinct arrangement of the same type of point defects is a notable structural aspect.