Electrodes For Rechargeable Lithium Batteries Research Articles

Synthesis, structure characterization and magnetic properties of nanosize LiCo1 − y Ni y O2 prepared by sol–gel citric acid route

Single phase LiCo1 − yNiyO2 (y = 0.4 and 0.5) with fine particles and high homogeneity was synthesized by “chimie douce” assisted by citric acid as the polymeric agent and investigated as positive electrodes in rechargeable lithium batteries. The long-range and short-range structural properties are investigated with experiments including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and superconducting quantum interference device magnetometry. The physicochemical properties of the powders (crystallinity, lattice constants, grain size) have been investigated in this composition. The powders adopted the α-NaFeO2 structure as it appeared from XRD and FTIR results. Magnetic measurements shows signal at low temperature attributed to the magnetic domains in the nanostructure sample from which we estimated that the cation mixing are 3.35 and 4.74% for y = 0.4 and 0.5 in LiCo1 − yNiyO2, respectively. LiCo0.5Ni0.5O2 cathode yields capacity (135 mAh g−1) compared to LiCo0.6Ni0.4O2 cathode (147 mAh g−1) when discharged to a cutoff voltage of 2.9 V vs. Li/Li+. Lower capacity loss and higher discharge efficiency percentage are observed for the cell of LiCo0.6Ni0.4O2 cathode.

Electrochemical Properties of Tin Oxide Electrode for Rechargeable Lithium Batteries

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Expansion and shrinkage of the sulfur composite electrode in rechargeable lithium batteries

The expansion and shrinkage characteristics of sulfur composite cathode electrode in rechargeable lithium batteries have been investigated. It was found that the sulfur composites electrodes expanded when discharging and shrank when charging again. The thickness change of the electrode was measured to be about 22%. The thickness of lithium metal anodes was also changed when lithium deposition and dissolution, while the sulfur composites electrodes expanded and shrank conversely. The investigation showed that the thickness changes of lithium anode and sulfur composite cathode could be compensated with each other to keep the total thickness of the cell not to change so much.

α‐MnO2 Nanowires: A Catalyst for the O2 Electrode in Rechargeable Lithium Batteries

α‐MnO₂ Nanowires: A Catalyst for the O₂ Electrode in Rechargeable Lithium Batteries

α‐MnO2 Nanowires: A Catalyst for the O2 Electrode in Rechargeable Lithium Batteries

Eine höhere Kapazität von Lithiumbatterien lässt sich mithilfe von α-MnO2-Nanodrähten als Katalysator in einer porösen Sauerstoff-Kompositkathode erreichen. Im rasterelektronenmikroskopischen Bild einer positiven Kompositelektrode sind Li2O2-Ablagerungen, die sich während des Entladevorgangs bilden, in einer porösen Matrix aus α-MnO2 und Kohlenstoff erkennbar. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2001/2008/z705648_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Electrochemical characterization of amorphous LiFe(WO 4) 2 thin films as positive electrodes for rechargeable lithium batteries

Amorphous LiFe(WO 4) 2 thin films have been fabricated by radio-frequency (R.F.) sputtering deposition at room temperature. The as-deposited and electrochemically cycled thin films are, respectively, characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, and X-ray photoelectron spectra techniques. An initial discharge capacity of 198 mAh/g in Li/LiFe(WO 4) 2 cells is obtained, and the electrochemical behavior is mostly preserved in the following cycling. These results identified the electrochemical reactivity of two redox couples, Fe 3+/Fe 2+ and W 6+/W x+ ( x = 4 or 5). The kinetic parameters and chemical diffusion coefficients of Li intercalation/deintercalation are estimated by cyclic voltammetry and alternate-current (AC) impedance measurements. All-solid-state thin film lithium batteries with Li/LiPON/LiFe(WO 4) 2 layers are fabricated and show high capacity of 104 μAh/cm 2 μm in the first discharge. As-deposited LiFe(WO 4) 2 thin film is expected to be a promising positive electrode material for future rechargeable thin film batteries due to its large volumetric rate capacity, low-temperature fabrication and good electrode/electrolyte interface.

Local structure and electrochemistry of LiNi y Mn y Co1 − 2y O2 electrode materials for Li-ion batteries

A series of LiNi x Mn y Co z O2 (x = y, z = 1 − 2y) oxides have been synthesized by “chimie douce” and investigated as positive electrodes in rechargeable lithium batteries. Layered LiNi y Mn y Co1 − 2y O2 materials with high homogeneity and crystallinity were synthesized using the wet-chemical method assisted by carboxylic acid as the polymeric agent. The long range and local structural properties are investigated with experiments including X-ray diffraction, Fourier transform infrared spectroscopy, and electron paramagnetic resonance spectroscopy. The evolution of the structure is discussed as a function of the cobalt content that confers layer-like behavior on the framework. Electrochemical performance of LiNi y Mn y Co1 − 2y O2 oxides is tested in cells using nonaqueous 1 M LiPF6 dissolved in ethylene carbonate–diethyl carbonate. Charge–discharge profiles are investigated as a function of the rate capability and the voltage window. A relation is found between the gravimetric capacity and the cation disorder of the positive electrode as indicated by structural analysis. Fast lithium extraction attributed to the larger interslab space has been observed in the cobalt-rich oxides.

Electrochemical performance and structural change during charge–discharge reaction of SnO–P2O5 glassy electrodes in rechargeable lithium batteries

Using melt quenching, SnO–P2O5 glasses were synthesized, and then characterized as negative electrode materials for lithium secondary batteries. The electrochemical cell Li/the 67SnO·33P2O5 (mol%) glass maintained reversible capacity of about 400mAhg−1 for 20 cycles. The cell’s cycle performance was better than those of cells using Sn-based crystals such as Sn, SnO, and SnO2 as working electrodes. The local structure of the 67SnO·33P2O5 glass after lithium insertion and extraction was analyzed. 7Li MAS-NMR measurements revealed that the Li–Sn alloy was formed during the first lithium insertion to the glass and that alloying–dealloying of the Li–Sn domain occurred during charge–discharge cycling. The glassy matrix surrounding the alloy was investigated using 31P MAS-NMR. The P2O74- group might be changed to PO43- and P2O64- groups by the first lithium insertion to the glass. The formed phosphate groups remained after the consecutive lithium extraction process. An all-solid-state cell with the 67SnO·33P2O5 glass exhibited the discharge capacity of 750mAhg−1 at the first cycle, which is greater than that of a cell with the 50SnO·50B2O3 glass.

Electrochemical Features of LiNiyMnyCozO2 Cathodes for Li-ion batteries

A series of LiNiyMnyCozO2 layered materials was synthesized by chimie douce and investigated as positive electrodes in rechargeable lithium batteries. Electrochemical performance of LiNiyMnyCozO2 oxides is tested cell using non-aqueous 1M LiPF6 dissolved in EC-DEC. Charge-discharge profiles are investigated as a function of the rate capability and the voltage window. A relation is found between the gravimetric capacity and the cation disorder of the positive electrode as indicated by structural analysis. A quite fast lithium extraction attributed to the larger interslab space has been observed in the cobalt-rich oxides.

Synthesis, Structure and Electrochemical Properties of LiNi0.33Mn0.33Co0.33O2 Positive Electrode for Rechargeable Lithium Batteries

The layered LiNi0.33Mn0.33Co0.33O2 materials were prepared by wet chemical method using oxalic acid as a polymeric agent. The positive LiNi0.33Mn0.33Co0.33O2 powders were characterized by means of X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and magnetometry. Electrochemical features of LiNi0.33Mn0.33Co0.33O2 positive electrodes were investigated as a function of synthesis conditions, cutoff voltage limit, and C-rate discharge current. Electrochemical properties are discussed in relation with the local structure and morphology of the layered materials.

Macroporous Li(Ni 1/3Co 1/3Mn 1/3)O 2: A high-rate positive electrode for rechargeable lithium batteries

Macroporous Li(Ni 1/3Co 1/3Mn 1/3)O 2 synthesized by a simple non-hydroxide route has been characterize as a high-energy and high-power positive electrode for rechargeable lithium batteries, exhibiting a discharge capacity of 195 mAh g −1 at 1 C (2244 Wh L −1) and 175 mAh g −1 at 10 C (2008 Wh L −1) and 99.99% capacity retention. Note the volumetric calculations are based on composite electrodes, not just the volume of the active material. Comparison between macroporous Li(Ni 1/3Co 1/3Mn 1/3)O 2 and the material synthesized by the conventional hydroxide method demonstrates that the latter shows a significant increase in polarization upon cycling whereas the former material does not. Cycling at 50 °C shows that the macroporous material does exhibit more polarization at elevated temperatures. Macroporous Li(Ni 1/3Co 1/3Mn 1/3)O 2 has been tested with a graphite negative electrode in a rocking-chair cell. Cycling was inferior to that with a Li metal negative electrode, but the origin of this may lie with the negative electrode. Powder X-ray diffraction also collected on macroporous Li(Ni 1/3Co 1/3Mn 1/3)O 2 after 100 cycles to 4.2 and 4.6 V, shows excellent structural stability, whereas cycling to 4.2 V induces a reduction in the Li/Ni site exchange from 4% to 2%, no significant change occurs for cycling to 4.6 V.

The lithium intercalation compound Li2CoSiO4 and its behaviour as a positive electrode for lithium batteries

The electrochemical behaviour of 3 polymorphs of the lithium intercalation compound Li2CoSiO4, betaI, betaII and gamma0, as positive electrodes in rechargeable lithium batteries is investigated for the first time.

The effect of cationic disordering on the electrochemical performances of the layered nitrides LiWN 2 and Li 0.84W 1.16N 2

The layered nitrides LiWN 2 and Li 0.84W 1.16N 2 are investigated related to their electrochemical performances as possible electrodes for rechargeable lithium batteries. In the case of LiWN 2, for which Li and W atoms are ideally ordered in alternating Li and W layers, de-intercalation of lithium proceeds up to 50%. The de-intercalated lithium can be intercalated again subsequently. The reversible reaction is the origin of the high cyclability observed in the corresponding lithium cells. On the other hand, in Li 0.84W 1.16N 2 the Li layers are statistically occupied by tungsten (16%) and lithium (84%). A clear effect of the disordered cationic occupation on the electrochemical behaviour has been found, since for Li 0.84W 1.16N 2 a very low extraction rate is obtained during the first oxidation (0.03 Li per formula unit). In addition, cyclability is rather poor. The very different electrochemical behaviour is explained by the structural differences between both layered nitrides.

Mesoporous and nanowire Co3O4as negative electrodes for rechargeable lithium batteries

The conversion reactions associated with mesoporous and nanowire Co(3)O(4) when used as negative electrodes in rechargeable lithium batteries have been investigated. Initially, Li is intercalated into Co(3)O(4) up to x approximately 1.5 Li in Li(x)Co(3)O(4). Thereafter, both materials form a nanocomposite of Co particles imbedded in Li(2)O, which on subsequent charge forms CoO. The capacities on cycling increase on initial cycles to values exceeding the theoretical value for Co(3)O(4) + 8 Li(+) + 8e(-) --> 4 Li(2)O + 3 Co, 890 mAhg(-1), and this is interpreted as due to charge storage in a polymer layer that forms on the high surface area of nanowire and mesoporous Co(3)O(4). After 15 cycles, the capacity decreases drastically for the nanowires due to formation of grains that are separated one from another by a thick polymer layer, leading to electrical isolation. In contrast, the mesoporous Co(3)O(4) losses its mesoporosity and forms a morphology similar to bulk Co(3)O(4) (Co particles imbedded in Li(2)O matrix) with which it exhibits a similar capacity on cycling. In contrast to mesoporous lithium intercalation compounds, which show superior capacity at high rates compared to bulk materials, mesoporosity does not seem to improve the capacity of conversion reactions on extended cycling. If, however, mesoporosity could be retained during the conversion reaction, then higher capacities could be obtained in such systems.

Pt-Embedded MoO[sub 3] Electrodes for Rechargeable Lithium Batteries

Effects of Pt nanoparticle incorporation into a MoO 3 thin film, which was prepared via cosputtering of a Pt and MoO 3 target, were investigated for a cathode electrode of the rechargeable Li batteries. The incorporation of the Pt with size of ca. 1.5 nm formed a heterogeneous film morphology with nanophases of Pt and MoO 3 domains, leading to a better cyclic performance than the electrode of MoO 3 without Pt. These enhancements with Pt in the MoO 3 electrode could be ascribed to a combined effect of substantial decrease in the sheet resistance and amelioration of the mechanical stability of the film itself.

An Overview of Chemically/Surface Modified Cubic Spinel LiMn2O4Electrode for Rechargeable Lithium Batteries

The present article is concerned with the overview of the chemically/surface modified cubic spinel <TEX>$LiMn_2O_4$</TEX> as a cathode electrode far lithium ion secondary batteries. Firstly, this article presented a comprehensive survey of the cubic spinel structure and its correlated electrochemical behaviour of <TEX>$LiMn_2O_4$</TEX>. Subsequently, the various kinds of the chemically/surface modified <TEX>$LiMn_2O_4$</TEX> and their electrochemical characteristics were discussed in detail. Finally, this article reviewed our recent research works published on the mechanism of lithium transport through the chemically/surface modified <TEX>$Li_{1-\delta}Mn_2O_4$</TEX> electrode from the kinetic view point by the analyses of the experimental potentiostatic current transients and ac-impedance spectra.

Highly Electrochemical Reaction of Lithium in the Ordered Mesoporosus β-MnO2

The highly crystallized β-MnO2 with the narrowest [1 × 1] channels prepared by direct thermal decomposition of Mn(NO3)2 does not provide much capacity due to the poor kinetics of the lithium intercalation/deintercalation process. In the present work, we report the preparation and electrochemical performance of an ordered mesoporous β-MnO2 as a positive electrode for rechargeable lithium batteries. The well-ordered mesoporous β-MnO2 prepared using mesoporous silica KIT-6 as a template by thermal decomposition of Mn(NO3)2 exhibits high initial capacity, reaching a chemical composition of Li0.75MnO2, and it also shows a good rate capability and cycling ability. The correlation between the specific mesoporous structure and the superior electrochemical performance was discussed in detail.

LiNi0.33Mn0.33Co0.33O2 Positive Electrode for Rechargeable Lithium Batteries

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Templated Nanocomposite Electrodes for Rechargeable Lithium Batteries

not Available.

Lithiated manganese oxide Li 0.33MnO 2 as an electrode material for lithium batteries

Li 0.33MnO 2 was prepared by solid-state reaction of CMD oxide and a lithium salt. The structure was studied by X-ray diffraction and Raman scattering during electrochemical discharging. The possibility of application as a positive electrode in rechargeable lithium batteries was investigated. The electrochemical properties of Li//Li 0.33MnO 2 cells were studied as a function of temperature in the range 25–55 °C. The electrode material delivers an initial capacity of 194 mAh g −1 and shows good reversibility at room temperature. Finally, the lithium insertion mechanism was examined by the determination of the ion kinetics.