fig4

Figure 4. Schematic illustration of full discharge-charge mechanism for FeF₂ electrode. (1) Forming disordered Fe and LiF at the surface. (2) Forming trirutile and rocksalt phases throughout the interior accompanied by formation of Fe and LiF particles with double-layered shell. (3) The shell limits the propagation of the reaction to the [001], creating a boundary between the converted (iron containing) and unconverted regions. (4) Fully discharged state with Fe nanoparticles nucleated on the fluoride matrix. (5) Charging proceeds with the consumption of these Fe nanoparticles. (6) This is followed by the reconversion of the double-layered shell and the re-formation of a pseudo-single-crystalline rutile nanorod. Reproduced from Ref.^[8] with permission. Copyright 2021 Springer Nature.