Preparation of yttrium doped lithium iron(II) phosphate as cathode material using solid state reaction

Abstract

Yttrium (Y) doped lithium iron (II) phosphate (LiFe1-xYxPO4) cathode materials were synthesized by using solid-state reaction. Yttrium (III) nitrate hexahydrate (H12N3O15Y) and yttrium (III) oxide (Y2O3) were used as the Y3+ ion sources. The solid state reaction was conducted using ball milling followed by annealing process. The samples were characterized using XRD, SEM and electrochemical measurements. The result shows that, independent to the ion source, the involving Y3+ did not change the orthorhombic structure of lithium iron (II) phosphate (LiFePO4). In other hand, the electrochemical impedance data reveal the increasing conductivity with the involving Y into the LiFePO4. The magnitude of the conductivity increasing is twofold when compared to the conductivity of pure LiFePO4. These results show the ability of rare earth element, namely Yttrium, to improve the properties of lithium ion cathode material.