Redox behavior and surface characterization of LiFePO4 in lithium hydroxide electrolyte

The redox behavior and surface characterization of LiFePO4 in aqueous lithium hydroxide (LiOH) electrolyte have been investigated. The objective of this work is to investigate the electrochemical behavior of LiFePO4 in an aqueous lithium hydroxide electrolyte and its comparison with that in non-aqueous lithium ion electrolytes. Cyclic voltammetry results show that LiFePO4 undergoes partially reversible oxidation/reduction. The products formed on electrooxidation and subsequent reduction of LiFePO4 were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). It is found that lithium extraction from LiFePO4 occurs during oxidation. The products formed on subsequent reduction consist of LiFePO4 and Fe3O4.