Structural and Electrochemical Characterizations of FeV3O8 as a Host Material for Rechargeable Li-ion Batteries

Abstract

We investigate how affected by intercalation chemistry of lithium ion into monoclinic FeV3O8 tunnel structure. By using high temperature solid state synthetic method, rod-type FeV3O8 powder could be obtained and then, confirm powder phase and morphology by using SEM and XRD. In order to determine lithium ion intercalation profiles into those structure, several structural and electrochemical features such as cyclic voltammetry, galvanostatic discharge/charge curve and XRD analysis were conducted. Although FeV3O8 as a positive electrode would be operated with unfavorable performance that could not be utilized to satisfy performances of EV needs given period of time, we discovered possibility of these material through structural and electrochemical studies during project. As a novel positive material, FeV3O8 vs. Lithium cell discharged at 0.2C (1C = 151.9mAh g-1) delivered 63.51mAh/g of reversible capacity with the electrochemically active redox reaction. In the voltage range between 2.0 – 3.5V, the cell exhibits one voltage plateaus with well- defined discharge voltage near 2.7 V, and a coulombic efficiency of approximately 99 percent. Unfortunately, FeV3O8 has poor high-rate performances, the cell exhibits a specific capacity of about 5 mAh g-1 at 10C. These results are caused to the crystallized particle morphology. We have been investigating several countermeasures for contributing lithium ion intercalation into FeV3O8 structure. In order to improve kinetic properties, the change of particle size and morphology to submicron size has to be considered. As an other example, additional coating process onto particles surface using high conductivity materials could be increased profiles of kinetic into the host materials. ⓒ 2016 DGIST