Comparative Study and Electrochemical Properties of LiFePO₄F Synthesized by Different Routes

Abstract

To improve the performance of LiFePO 4 F, a novel sol-gel process is developed. For comparison, ceramic process is also implemented. From X-ray diffraction results we know that each sample adopts a triclinic P1 space group, and they are isostructural with amblygonite and tavorite. The scanning electron microscope images show that the homogeneous grains with the dimension of 300-500 nm is obtained by the sol-gel process; meanwhile the sample particles obtained by ceramic process are as big as 1000-3000 nm. By galvanostatic tests and at electrochemical impedance spectroscopy method, the sample obtained by sol-gel process presents better electrochemical properties than the one obtained by ceramic process.

One-pot synthesis of Li2FePO4F nanoparticles via a supercritical fluid process and characterization for application in lithium-ion batteries

“…In addition, the incorporation of a second Li + ion in Li 2 MPO 4 F (M ¼ Fe, Co, Mn) materials may lead to a specic capacity of about 290 mA h g À1 , nearly that of silicate based cathode materials. The structural and electrochemical characteristics of Li 2 /Na 2 FePO 4 F were reported earlier by Nazar et al [3][4][5] and several reports are available on the synthesis of uorophosphates via solid state reactions, 5,9 sol-gel processes 10 and hydrothermal or solvothermal routes using water, organic solvents 8,11,12 and ionic liquids as reaction media. 13,14 Among these methods, the hydrothermal and solvothermal processes have proved to be benecial in terms of cost, time and energy savings.…”

A novel cationic-ordering fluoro-polyanionic cathode LiV0.5Fe0.5PO4F and its single phase Li+ insertion/extraction behaviour

“…In comparison with the reported CV curves of LFPF and LVPF, we also conrm that the Fe 3+ /Fe 2+ and V 3+ /V 4+ redox couples are responsible for the redox peaks observed in the voltage ranges of 2.0-3.6 V and 3.6-4.7 V, respectively. 10,20,26 Equally important to note is the shape of the CV peaks. The broad shape of the CV peaks, instead of the sharp and narrow peaks as observed in LVPF, is indicative of a single-phase solid solution behaviour.…”

Review on Synthesis, Characterizations, and Electrochemical Properties of Cathode Materials for Lithium Ion Batteries

“…Na 3 V 2 (PO 4 ) 2 F 3 classified as the most important among fluorophosphate materials due to the high theoretical capacity 192 mAh/g and its flexibility to be used as a cathode in both Li-ion batteries and Na-ion batteries [214]. While Na 1.5 VOPO 4 F 0.5 delivered through 3.6 and 4 V vs. Na + /Na theoretical capacity equal to 156 mAh/g [217][218][219][220][221].…”