Fe K-Edge X-ray Absorption Near-edge Spectroscopy and Morphology Analyses of LiFePO4 Powders
Nihlatunnur(a), C Latif(a), V S I Negara1(a), W Wongtepa(b) and S Pratapa(a*)
a) Department of Physics, Faculty of Sciences, Institut Teknologi Sepuluh Nopember (ITS), Jl. Arief Rahman Hakim, Surabaya 60111 , Indonesia
*suminar_pratapa[at]physics.its.ac.id
b) Synchrotron Light Research Institute (SLRI), Nakhon Ratchasima , Thailand
Abstract
Two LiFePO4 powders have been synthesized, i.e. using natural ironstone and commercial FeCl2•4H2O product as Fe sources, and their characteristics were compared. The x-ray absorption near-edge spectroscopy (XANES) data, Transmission Electron Microscope (TEM) images and Scanning Electron Microscope (SEM) micrographs were used to examine the value of E0 and the oxidation number, determine the crystallite sizes, and determine their morphology, respectively. Results showed that the ironstone- and commercial-based LFP powders exhibited E0 values of 7120.2 and 7119.6 respectively which are both almost equal to FeO and indicates that they have an oxidation number of 2+ as expected. In addition, the crystallite size of the ironstone-based LFP was smaller than that of the commercial one. Moreover, the SEM images showed that the natural LFP was more homogeneous than the commercial LFP.
Keywords: LiFePO4, ironstone, commercial precursor, XANES, crystallite size, morphology.
Topic: Synthesis and Characterization Techniques