LiNiO

Although LiNiOj is cheaper than LiCoOj and is capable of a rechargeable capacity 130 mAh g when charged to 

Several attempts have been made to synthesize a layered LiMn02 structure, isostructural with that of LiCo02 [57-61]. 

I The Structural Stability of Transition Metal Oxide Insertion Electrodes for Lithium Batteries 

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Figure 53. Discharge characteristics of LiNiO, and LiCoO, synthetized in air or oxygen (current density 0.25 mA cm 2 ).

LiMn02 are often mentioned as positive electrode materials instead of LiCo02 [87]. LiNiOz is desirable because it offers a larger capacity and lower cost than LiCo02, and it is expected that a LiNiO 2-graphite cell will be commercialized in the near future. 

Figure 6. Thermogravimetric curves for I l08,Li0 ]5NiOi in air. The heating and cooling rates were 5 °Cmin 1. The sample was prepared by electrochemical oxidation of LiNi02 without addition of conductive binder to 4.8V using an Li/LiNiO, cell, washed with DME and THF, and dried under vacuum at room temperature.

In comparison to SLC-1015 graphite, one cell was tested with 92wt% SL-20 vs. LiNio.80Coo.15Alo.05O2 in 1.2M LiPF6, EC/PC/MEC (3/3/4) by the same procedure and conditions described earlier. The ASI vs. DOD plot is shown in Figure 7. 

Figure 6. Power capability of cell using surface treated natural graphite SLC1015 as anode, and,LiNio.8oCoo.isAl0.osi cathode in 1.2MLiPF6, EC/PC/MEC (30 30 40 wt%).

High-power Li-ion cells with a LiNio.8Coo.15Alo.05O2 cathode, a synthetic graphite anode, 1.2 M LiPF6 + ethylene carbonate + ethyl-methyl carbonate (EC/EMC) electrolyte, and a Celgard 2300 separator, were... 

Figure 1. Average Raman microscope spectra of the fresh composite LiNio.sCoonAlo.05O2 cathode (a), and the cathode from cells that exhibited 10 (b),...

Julien, C., Letranchant, C., Lemal, M., Ziolkiewicz, S., Castro-Garcia, S., Layered LiNio 5Coo 502 compounds synthesized by a glycine-assisted combustion method for lithium batteries, J. Mater. Sci. 37,2367-2375 (2002). 

Figure 15. Ragone plot for LiNio.5Mno.5O2 showing the capacity of the cathode as a function of the discharge current density (data from ref 258).

Little is known about the electrical conductivity of the 550 material. One measurement shows a conductivity of 6 X 10 S/cm at 25 °C for the fully lithiated LiNio 5Mno.502. The magnetic susceptibility exhibits Curie—Weiss behavior at elevated temperatures. ... 

Figure 16. Neutron powder diffraction pattern of a iayered substituted nickeiate, LiNio.4Mno.4Coo.2O2.

Figure 19. Magnetic behavior of LiNio.5Mno.5O2, LiNio.4-Mno.4Coo.2O2, and LiNio.33Mno.33Coo.33O2 (a) susceptibility and (b) field effect (after Ma et al.).276...

XPS studies have been made on a number of compositions of these transition-metal oxides, and all indicate predominantly divalent nickel. Thus, for the 442 compound the Co spectrum is clearly Co +, and the Mn spectrum can be assigned to 80% Mn" + with 20% Mn +. The Ni spectrum is characterized by an intense and complicated satellite structure and consistent with 80% NP+ and 20 NP+. Studies on LiNio.33Mno.33Coo.3302, LiNio.5Mno.502, and... 

Figure 20. Electrochemical behavior of LiNio.4Mno.4-C00.2O2 (a) capacity as a function of a cycle at 1 and 2 mA/cm (reproduced with permission from ref 219, copyright 2004 The Royal Society of Chemistry) and (b) capacity as a function of discharge rate, average capacity of first five cycles. Cutoff on charge, 4.3 V at 22 °C Ngala, 4.4 V at 30 X Oh,278 4.4 V at 30 X Lu,2i6 and 4.2 V at 30 X...

Similar irreversible processes have been previously observed by Aurbach et al. on LiNi02 ° and Croce et al. on LiNio.75Coo.2502 ° by slow scan cyclic volta-mmetric (SSCV) measurements. However, in their EIS studies the former authors did not observe any obvious potential-dependence for the resistance associated with the surface layer ° but rather an invariant resistance in the range between 3.6 and 4.2 V. This latter observation is in direct disagreement... 

Figure 22. C Is, O Is, F Is, P 2p, Li Is, and Ni 2p XPS spectra for LiNio.8Coo.2O2 cycled in LiPFe/EC/DEC. (Reproduced with permission from refs 294 (Figure 6). Copyright 2002 The Electrochemical Society.)...

More recent XPS studies were conducted by Ander-sson et al. on a similar LiNio.8Coo.2O2 cathode cycled in LiPFe/EC/DEC. and more detailed efforts were made to assign the signature signals for various... 

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