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Hunter, W. R.

doi:10.1016/b978-012617560-8/50017-7

Cited by 2 publications

(2 citation statements)

References 77 publications

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“…This refinement was completed using Rietica for Windows 2.1. 29 In the first step of the refinement only the lattice parameters, phase scales and background were adjusted. After this process the lattice parameters were restrained and the peak shape parameters were refined.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Lithium Content and Core to Shell Ratio on Structure and Electrochemical Performance of Core-Shell Li_(1+x)[Ni_0.6Mn_0.4]_(1−x)O₂Li_(1+y)[Ni_0.2Mn_0.8]_(1−y)O₂Positive Electrode Materials

Camardese

Abarbanel

et al. 2014

J. Electrochem. Soc.

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Core-shell positive electrode materials with a core:shell mass ratio of 2:1 and 4:1 were synthesized in a two-step reaction. Powder X-ray diffraction, SEM and spatial EDS measurements were used to characterize the core and shell phases in the precursors and lithiated products. It was determined using EDS that the precursor and lithiated products are both core-shell and the two phases can be easily resolved with laboratory grade XRD equipment. Two phase Rietveld refinement was completed on the core-shell lithiated products. The results of these refinements in conjunction with contour plots of the lattice parameters within the Li-Ni-Mn oxide layered single phase region were used to position the core and shell of each sample on the Li-Ni-Mn-O phase diagram as a function of the amount of Li 2 CO 3 used in synthesis. The shell phase retained an approximately fixed amount of Li while the Li content of the core phase increased as the overall Li content of the core-shell sample increased. Both the core and shell were electrochemically active. A specific capacity of 220 mAh/g was achieved in a core shell material between 2.5-4.6 V vs. Li/Li + . © The Author ( There has been an extraordinary effort to synthesize and characterize different materials for the positive electrode of lithium-ion batteries.1,2 A primary motivation of this research is to improve the performance of lithium-ion cells to meet requirements for electric vehicle (EVs) and grid storage applications. As the choices of positive electrode materials move away from current commercial staples such as LiFePO 4 5 the cell must be charged to higher potentials, sometimes as high as 4.8 V vs. Li/Li + , to access the additional reversible capacity. At higher potentials, degradation of the electrolyte through oxidation on the positive electrode may vastly reduce the lifetime of the cell. For the high energy density of new materials to be fully utilized, oxidation of the electrolyte must be minimized. Otherwise, these materials are of little commercial interest for EVs and grid storage where lifetime requirements of decades of useful service would be difficult to achieve.The rate of parasitic reactions that degrade the electrolyte at the positive electrode's surface are affected by the composition of the electrolyte, the potential of the positive electrode, the composition of the positive electrode and many other parameters in the construction and operation of the cell. Commonly, researchers are addressing this by improving electrolyte formulations via additives and solvent blends.6,7 A complementary approach is examining the positive electrode surface composition and its effect on the degradation of the electrolyte. [8][9][10][11][12] Rowe et al. 13 showed via high precision charger measurements that the columbic efficiency and charge end point capacity slippage were dependent on the composition of the positive electrode of various LiNi-Mn layered oxides. Samples in that study were cycled up to 4.6 V vs. Li/Li + with the same additive-free electrolyte formulation. ...

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Section: Resultsmentioning

confidence: 99%

The Effect of Lithium Content and Core to Shell Ratio on Structure and Electrochemical Performance of Core-Shell Li_(1+x)[Ni_0.6Mn_0.4]_(1−x)O₂Li_(1+y)[Ni_0.2Mn_0.8]_(1−y)O₂Positive Electrode Materials

Camardese

Abarbanel

et al. 2014

J. Electrochem. Soc.

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“…Figure 1 shows the X-ray diffraction ͑XRD͒ patterns of a commercial sample of the NMC-oxide precursor reported by Yabuuchi et al 19 and of the pattern of Ni 1/3 Mn 1/3 Co 1/3 ͑OH͒ 2 calculated using Rietica software. 21 The difference between the two XRD patterns ͑peak positions and shapes͒ indicates that this commercial precursor to Li͓Ni 1/3 Mn 1/3 Co 1/3 ͔O 2 is not the pure hydroxide, Ni 1/3 Mn 1/3 Co 1/3 ͑OH͒ 2 .…”

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confidence: 98%

Synthesis of Spherical and Dense Particles of the Pure Hydroxide Phase Ni[sub 1∕3]Mn[sub 1∕3]Co[sub 1∕3](OH)[sub 2]

Bommel¹,

Dahn

2009

J. Electrochem. Soc.

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The structure of the coprecipitated precursor to the positive electrode material, Li[Ni1∕3Mn1∕3Co1∕3]normalO2 (NMC), is typically synthesized via a coprecipitation reaction and assumed to be normalNi1∕3normalMn1∕3normalCo1∕3(OH)2 or normalNi1∕3normalMn1∕3normalCo1∕3OOH . The coprecipitation reaction and its products are not thoroughly understood. Here, pure phase normalNi1∕3normalMn1∕3normalCo1∕3(OH)2 is synthesized in the presence of aqueous ammonia, yielding dense and spherical particles. normalNi1∕3normalMn1∕3normalCo1∕3(OH)2 was found to readily oxidize in air, especially during heating. The obtained product was analyzed with powder X-ray diffraction and thermogravimetric analysis. The results indicate that normalNi1∕3normalMn1∕3normalCo1∕3(OH)2 undergoes oxidation to the oxyhydroxide phase, normalNi1∕3normalMn1∕3normalCo1∕3OOH . Heating also resulted in an increase in tap density of the oxyhydroxide; the final tap density of the material was found to be 2.0gcm−3 .

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Windows and Filters

Cited by 2 publications

References 77 publications

The Effect of Lithium Content and Core to Shell Ratio on Structure and Electrochemical Performance of Core-Shell Li_(1+x)[Ni_0.6Mn_0.4]_(1−x)O₂Li_(1+y)[Ni_0.2Mn_0.8]_(1−y)O₂Positive Electrode Materials

The Effect of Lithium Content and Core to Shell Ratio on Structure and Electrochemical Performance of Core-Shell Li_(1+x)[Ni_0.6Mn_0.4]_(1−x)O₂Li_(1+y)[Ni_0.2Mn_0.8]_(1−y)O₂Positive Electrode Materials

Synthesis of Spherical and Dense Particles of the Pure Hydroxide Phase Ni[sub 1∕3]Mn[sub 1∕3]Co[sub 1∕3](OH)[sub 2]

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Cited by 2 publications

References 77 publications

The Effect of Lithium Content and Core to Shell Ratio on Structure and Electrochemical Performance of Core-Shell Li(1+x)[Ni0.6Mn0.4](1−x)O2Li(1+y)[Ni0.2Mn0.8](1−y)O2Positive Electrode Materials

The Effect of Lithium Content and Core to Shell Ratio on Structure and Electrochemical Performance of Core-Shell Li(1+x)[Ni0.6Mn0.4](1−x)O2Li(1+y)[Ni0.2Mn0.8](1−y)O2Positive Electrode Materials

Synthesis of Spherical and Dense Particles of the Pure Hydroxide Phase Ni[sub 1∕3]Mn[sub 1∕3]Co[sub 1∕3](OH)[sub 2]

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The Effect of Lithium Content and Core to Shell Ratio on Structure and Electrochemical Performance of Core-Shell Li_(1+x)[Ni_0.6Mn_0.4]_(1−x)O₂Li_(1+y)[Ni_0.2Mn_0.8]_(1−y)O₂Positive Electrode Materials

The Effect of Lithium Content and Core to Shell Ratio on Structure and Electrochemical Performance of Core-Shell Li_(1+x)[Ni_0.6Mn_0.4]_(1−x)O₂Li_(1+y)[Ni_0.2Mn_0.8]_(1−y)O₂Positive Electrode Materials