Synthesis, Characterization, and Electrochemical Studies of LiNi 4 (PO 4 ) 3

1. Synthesis, Characterization, and Electrochemical Studies of LiNi4(PO4)3 Lamartine Meda, Xavier University of Louisiana, DMR 0934111 Development of new battery materials for application in electric vehicles, cell phones, smart cards, and medical technologies are needed to keep up with consumer demands. (a) (b) a • Funded by NSF-DMR, researcher at Xavier University of Louisiana are focusing on developing new materials based on LiSICON (Lithium Super Ionic Conductor) type material). Here we are reporting on the synthesis of LiNi4(PO4)3 by the Pechini type sol-gel method. A stable phase of this material was obtained after annealing at 750C/5h and no phase changes were observed at higher temperatures. (c) (d) d Fig. 1 shows the powder x-ray diffraction which is similar to that of mononoclinicLiSICON/NaSICON systems. Therefore, assuming monoclinc lattice, lattice parameters are derived by using the POWD software. Scanning electron microscopy shows the crystallite size is about 150 -200 nm for samples annealed at 750 C/5h. The FT-IR spectrum (not shown) exhibits strong absorptions below 1,500 cm–1, which correspond to PO4 unit. Fig. 1 shows the characterization of LiNi4(PO4)3 by (a) X-ray diffraction (b) scanning electron microscopy, (c) AC impedance showing the cole-coleplot,(d) slow scan cyclic voltammogram (CV)at a scan rate of 0.1 mV/s vs. Li+/Li between 1.5 and 3.5 V. • The calculated ionic conductivity from the complex impedance (Cole–Cole) plot of real (Zreal) as a function of imaginary (Zimag) was 3.5 x 10-6 S cm-1. The cyclic voltammetry profile demonstrated the electrochemical reversibility of the material and exhibits the oxidation and reduction peaks that correspond to Ni2+/Ni 3+