Fig. 3: TEM Characterization of FePO₄ particles.

a Before Li extraction; b after Li extraction; c after Li release. From left to right: TEM image of FePO₄ particle, Fe Energy-dispersive X-ray (EDX) elemental mapping, Na EDX elemental mapping, and Li Electron energy loss spectroscopy (EELS) elemental mapping (the color bar legend is only for Li elements).