Synthesis and characterization of LiFePO4/C composite obtained by sonochemical method

Abstract

Lithium iron phosphate has become of great interest as storage cathode for the next generation of rechargeable lithium batteries. Olivine structure LiFePO 4 /C composite powder was prepared by ultrasound assisted synthesis. A polyvinyl alcohol solution was used as the source of an in situ formed carbon. X-ray powder diffraction confirmed the phase purity. X-ray powder diffraction data were used for the crystal structure refinement, based on Rietveld full profile method. All relevant structural and microstructural crystal parameters that could be significant for electrochemical intercalation/deintercalation processes were determined. The Rietveld refinement also showed additional electron density on the lithium sites, indicating 3 at.% iron on the lithium site. Electrochemical characteristic of the composite was evaluated by using galvanostatic charge/discharge tests. While cycling at C/3 (C/10) rate the discharge capacity increases, starting from the value of 94.1 (116.0) mAh/g and reaching 99.5 (124.0) mAh/g at the end of the cycling. Particle morphology was revealed by both scanning and transmission electron microscopies. On the thin particle edges carbon film with a typical thickness of several nanometers can be observed, as well as small carbon agglomerates (typical size <6 nm) at certain spots on the substrate surface.

Development and Characterization of Titanium Phosphates (Tip2o7) and Lithium Titanium Phosphate (Litip2o7) and Their Thermal and Electric Properties.

“…918 synthesis process [8], microwave-solvothermal synthesis method [9], sol-gel synthesis technique [10], spray pyrolysis technique [11], co-precipitation technique [12], carbothermal reduction technique [13] and many more techniques [14].…”

Sonoprocessing of LiFePO4 nanoparticles and nanocomposites for cathode material in lithium ion batteries

“…The use of lithium ion batteries in large-scale commercial applications is avoided since the oxygen release at higher temperatures can cause explosion [5]. A number of attempts were made to overcome these limitations [6][7][8]. Electron transport of these materials was enhanced by applying conducting layer around LiFePO 4 , which includes silver [8], carbon-based materials [6,7], conducting polymers [9][10][11], and doping of LiFePO 4 using foreign conducting materials [9,10].…”

“…A number of attempts were made to overcome these limitations [6][7][8]. Electron transport of these materials was enhanced by applying conducting layer around LiFePO 4 , which includes silver [8], carbon-based materials [6,7], conducting polymers [9][10][11], and doping of LiFePO 4 using foreign conducting materials [9,10]. Secondly, the improvement in capability of LiFePO 4 materials was carried out by increasing the surface area by reducing the particle size and use of a uniform narrow particle size distribution [12][13][14][15][16][17].…”

Enhanced electrochemical performance of nano-sized LiFePO4/C synthesized by an ultrasonic-assisted co-precipitation method

“…Yi et al [32] reported that LiAl 0.05 Mn 1.95 O 4 powder with uniform, nearly cubic structure and octahedral morphology with narrow size distribution can be obtained by the ultrasonic-assisted sol-gel method. With this advantage, Jugovic et al [33] reported that LiFePO 4 /C composite powder was prepared using a sono-chemical reaction by the application of powerful ultrasound radiation (20 kHz). However, this material exhibited a lower discharge capacity (94 and 124 mAh g −1 at C/3 and C/10, respectively) due to the dislocation of iron ions on lithium sites (3%), which could block the whole channel and prevent lithium motion.…”