Novel lithium iron pyrophosphate (LiFe 1.5P 2O 7) as a positive electrode for Li-ion batteries
Journal
Chemistry of Materials
Series/Report No.
Chemistry of Materials
Journal Volume
19
Journal Issue
22
Date Issued
2007-10-30
Author(s)
Abstract
Lithium iron pyrophosphate (LiFe 1.5P 2O 7) has been synthesized by a wet-chemical method for application in lithium-ion batteries. Structural analysis using X-ray diffraction and high-resolution electron microscopy indicate that LiFe 1.5O 7 synthesized at 500°C, using metal acetates, is crystallized in the monoclinic structure with lattice parameters a = 0.698 76 nm, b = 0.812 36 nm, c = 0.964 22 nm, and β=111.83° (P2 1/c space group). Electrochemical characterization of LiFe 1.5O 7 in lithium cells indicates a capacity of 95 mA·h/g obtained in the voltage range 2.5-4.2 V. The resulting incremental capacity indicates a stable structure for the first cycle with the redox peaks at 3.33 and 3.22 V versus Li 0/Li +. The capacity of LiFe 1.5P 2O 7 decreased with cycling number at the rate of 0.22% per cycle while the capacity falls off rapidly in the case of material prepared at higher temperatures.
Subjects
Crystallization
Electrochemical electrodes
High resolution electron microscopy
Lattice constants
Lithium batteries
Synthesis (chemical)
X ray diffraction
Electrochemical characterization
Lithium iron pyrophosphate
Monoclinic structure
Lithium compounds
Type
journal article