Confirmation of the domino-cascade model by lifepo4/fepo 4 precession electron diffraction
A recent transmission electron microscopy (TEM) method using precession electron diffraction (PED) was used to obtain LiFePO4 and FePO 4 phase mapping at the nanometer-scale level on a large number of particles of sizes between 50 and 300 nm in a partially charged cathode. Despite the similarity of the two phases (the difference of lattice parameters is <5%), the method gives clear results that have been confirmed using high-resolution transmission electron microscopy (HRTEM) and energy-filtered transmission electron microscopy/electron energy loss spectroscopy (EFTEM/EELS) experiments. The PED maps show that the particles are either fully lithiated or fully delithiated and, therefore, bring a strong support to the domino-cascade model at the nanoscale level (scale of a particle). A core-shell model or spinodal decomposition at mesoscale (scale of agglomerates of particles) is possible. Size effects on the transformation are also discussed. © 2011 American Chemical Society.
Keywords: Agglomeration ; Core-shell model ; electron diffraction ; Electron energy loss spectroscopy ; Electrons ; Energy dissipation ; Energy filtered transmission electron microscopy ; Energy-loss spectroscopy ; High resolution electron microscopy ; High resolution transmission electron microscopy ; LiFePO ; LiFePO4 ; Lithium ; Lithium alloys ; lithium batteries ; Mesoscale ; Nano-meter-scale ; Nanoscale levels ; phase mapping ; Phase mappings ; precession electron diffraction ; Size effects ; Spinodal decomposition ; Stream flow ; TEM ; Transmission electron microscopy
Record created on 2014-11-14, modified on 2016-08-09