Li-ion kinetics in LiFePO 4 /carbon nanocomposite prepared by a two-step process: The role of phase composition
| Autor: | Sourav Khan, Adriyan Milev, Parasuraman Selvam, G. S. Kamali Kannangara, Laurel George |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
General Chemical Engineering Reducing atmosphere Diffusion Kinetics Analytical chemistry 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Ascorbic acid Electrochemistry 01 natural sciences 0104 chemical sciences Dielectric spectroscopy Phase (matter) Hydrothermal synthesis 0210 nano-technology |
| Zdroj: | Electrochimica Acta. 209:565-573 |
| ISSN: | 0013-4686 |
| Popis: | LiFePO 4 /Carbon nanocomposite was synthesised by two-step procedure hydrothermal synthesis in the presence of ascorbic acid followed by mixing of the product with citric acid and heating at 600 °C under a reducing atmosphere. During the first-step, slab or cuboid-shaped LiFePO 4 particles were formed with sizes of ∼100–150 nm in width and ∼300–600 nm in length. The second-step produced deformed slab or cuboid-like LiFePO 4 /Carbon nanocomposite with shapes somewhat resembling that of the precursor. The electrochemical properties were examined by electrochemical impedance spectroscopy (EIS) and potentiostatic intermittent titration technique (PITT) at a series of equilibrium potentials within the voltage range 2.7–4.2 V. From the PITT measurements of cathodes with two thicknesses, the LiFePO 4 /Carbon nanocomposite exhibits a specific discharge capacity of 150.3 mAh/g and 164.3 mAh/g, for 9.4 μm and 6.9 μm thickness, respectively. The current relaxation measurements also showed that the kinetics of Li-ion transfer depends strongly on the phase composition; in the solid-solution regions the Li-ion kinetics is dominated by diffusion whereas in the two-phase region it is by phase transformation. |
| Databáze: | OpenAIRE |
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