Temperature Effects on the Behavior of Lithium Iron Phosphate Electrodes

Russian Journal of Electrochemistry - The systematic study of the effect of temperature (in the range from ?45 to +60°C) on the process of lithium extraction from LiFePO4 and its...     

Effect of porous structure of LiCoPO4 on its performance in hybrid supercapacitor

Journal of Solid State Electrochemistry - Hybrid supercapacitors (HSCs) based on the mechanochemically prepared LiCoPO4 samples with different specific surface area and porosity as cathodes and the...     

Temperature Effect on the Behavior of a Lithium Titanate Electrode

Russian Journal of Electrochemistry - The effect of temperature (over the–15 to +60°С range) on the insertion of lithium into Li4Ti5O12 is systematically studied. At a current of...     

Minimal irreversible capacity caused by the lithium insertion into materials of negative electrodes in lithium-ion batteries

The minimal irreversible capacity of negative electrodes of lithium-ion batteries, necessary for their stable operation, is theoretically evaluated. The theoretical values are compared with real ones reported in literature. It is shown that the real values of the irreversible capacity for electrodes made of carbonaceous materials exceed several times the minimal required values; the real irreversible capacity of silicon-based electrodes exceeds the minimal values by 2 to 3 orders of magnitude.     

Electrochemical insertion of sodium into nanostructured materials based on germanium

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The possibility of electrochemical lithium intercalation into a nanodiamond

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The Effect of Particle Size on the Processes of Charging and Discharging of the LiFe<Subscript>0.97</Subscript>Ni<Subscript>0.03</Subscript>PO<Subscript>4</Subscript>/C/Ag Cathode Material

Olivine-structured LiFe_0.97Ni_0.03PO₄/C/Ag nanomaterials of varying dispersibility are prepared by using sol–gel synthesis with subsequent milling. The materials are certified using X-ray diffraction analysis, scanning electron microscopy, low-temperature nitrogen adsorption, and electrochemical testing under the lithium-ion battery operating conditions. The LiFe_0.97Ni_0.03PO₄/C/Ag cathode material primary particles’ size was shown to decrease, under the intensifying of ball-milling, from 42 to 31 nm, while the material’s specific surface area increased from 48 to 65 m²/g. The discharge capacity, under slow charging–discharging (C/8), approached a theoretical one for all materials under study. It was found that under fast charging–discharging (6 C and 30 C) the discharge capacity is inversely proportional to the particles’ mean size. The discharge capacity under the 6 С current came to 75, 94, 97, and 106 mA h/g for the initial material and that milled at a rotation velocity of 300, 500, and 700 rpm, respectively. An increase in the lithium diffusion coefficient upon the samples’ intense milling is noted.     

Lithium Intercalation into Nanostructured Films Based on Oxides of Tin and Titanium

The lithium intercalation into nanostructured films of mixed tin and titanium oxides is studied. X-ray diffraction and Moessbauer spectroscopy analyses reveal that films consist of a rutile solid solution (Sn, Ti)O₂ and an amorphous tin oxide enriched with Sn²⁺ ions. The films specific capacity during the first cathodic polarization in a 1 M lithium imide solution in dioxolane is 200–700 mA h/g, of which nearly one half is the irreversible capacity. During the second cycle, the latter is 15% of that in the first cycle. As the films are thin (<1 m), their capacity does not depend on the current density at 1–80 mA/g. During the electrode cycling, the capacity decreases by 2 mA h/g each cycle. The effective lithium diffusion coefficient, determined by a pulsed galvanostatic method, is 10^–11 cm²/s; it slightly increases with the film lithiation. During the first cycle, the amorphous phase of oxides is reduced to tin metal, the solid solution (Sn, Ti)O₂ decomposes, SnO₂ disperses to become an x-ray amorphous phase, and TiO₂ precipitates as a rutile phase. Lithium reversibly incorporates into the tin metal, yielding Li _y Sn, and into a disperse SnO₂ phase, yielding Li _x SnO₂.     

Study of the “Diamond—Pyrolytic Carbon” nanocomposites using lithium intercalation

Electrochemical behavior of the diamond-based composites: a nanodiamond—pyrocarbon composite and Carbal, as well as vacuum-high-temperature-annealed polycrystalline diamond is studied by the cathodic lithium incorporation from LiPF ₆ solution in a (1 : 4) propylene carbonate—diethyl carbonate mixture. The amount of incorporated lithium steadily increases with the nondiamond (graphite-like) carbon content in the composite. The intercalation capacity of Carbal equals ~33 mA-h per g of the graphite-like carbon. It is concluded that the graphite-like carbon distributed in the nano-(or micro-)diamond carcass is the electrochemically active phase in the composites.Translated from Elektrokhimiya, Vol. 40, No. 12, 2004, pp. 1508–1513.Original Russian Text Copyright © 2004 by Pleskov, Kulova, Skundin, Krotova, Ralchenko, Korchagina, Gordeev.     

Active Layer Thickness Effect on the Behavior of Electrodes Based on Lithium Iron Phosphate

Russian Journal of Electrochemistry - The effect of the active layer thickness (the amount of active material per unit area of the electrode) on the behavior of electrodes based on lithium iron...