Effect of operating parameters on synthesis of lithium iron phosphate (LiFePO4) particles in near- and super-critical water

Abstract

Hydrothermal synthesis of lithium iron phosphate (LiFePO4) particles in near- and super-critical water was investigated in a batch reactor system. The phase identification and morphology of synthesized LiFePO4 particles were performed by Fourier Transform Infrared (FT-IR), powder X-ray diffraction (XRD) and field emission scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX). The effect of operating parameters including temperature (400–450°C), pressure (200, 275 and 350bar) and reaction time (10 and 60min) were examined on particle size, size distribution, purity, crystalline structure, morphology, and electrochemical performance of the synthesized LiFePO4 in the presence of sodium sulphite (Na2SO3) as reducing agent. Highly crystalline LiFePO4 particles were synthesized at near-critical conditions (400°C, 200bar and 60min) with initial discharge capacity of 87mAhg−1 at 0.1 C-rate.