[摘要]:The three-dimensionally isolated morphology of secondary iron phosphide phases in a polycrystalline LiFePO(4) matrix is determined using a combination of electron tomography in high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), energy-dispersive X-ray spectroscopy (EDS), and electron energy-loss spectroscopy (EELS). The present evidence shows that the enhanced bulk electronic conductivity in LiFePO(4) has no relation to secondary metallic phases at the grain boundaries.