Growth and ionic conductivity of γ-Li3PO4

Ivanov-Shitz, A. K.; Kireev, V. V.; Mel'Nikov, O. K.; Demianets, L. N.

doi:10.1134/1.1405880

Cited by 46 publications

(36 citation statements)

References 5 publications

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“…Combining these interstitial values of E m with the minimum values of E f quoted above, we estimate the activation energies for intrinsic defects listed in Table VIII. The calculated activation energies for ␥-Li 3 PO 4 agree very well with the single crystal measurements of Ivanov-Shitz et al 8 Not only is there good numerical agreement, but also the fact that the activation energies for the b and c axes are the same can be understood. In Sec.…”

Section: Formation Energies For Vacancy-interstitial Pairs Of Intsupporting

confidence: 73%

Mechanisms ofLi+diffusion in crystallineγ- andβ−Li3
Du
¹
,
Holzwarth
²

2007
Phys. Rev. B
99
5
51
0
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Recently, there has been significant interest in developing solid-state lithium ion electrolytes for use in batteries and related technologies. We have used first-principles modeling techniques based on densityfunctional theory and the nudged elastic band method to examine possible Li ion diffusion mechanisms in idealized crystals of the electrolyte material Li 3 PO 4 in both the ␥ and ␤ crystalline forms, considering both vacancy and interstitial processes to find the migration energies E m . We find that interstitial diffusion via an interstitialcy mechanism involving the concerted motion of an interstitial Li ion and a neighboring lattice Li ion may provide the most efficient ion transport in Li 3 PO 4 . Ion transport in undoped crystals depends on the formation of vacancy-interstitial pairs requiring an additional energy E f , which results in a thermal activation energy E A = E m + E f / 2. The calculated values of E A are in excellent agreement with single crystal measurements on ␥-Li 3 PO 4 . Our results examine the similarities and differences between the diffusion processes in the ␥ and ␤ crystal structures. In addition, we analyze the zone center phonon modes in both crystals in order to further validate our calculations with experimental measurements and to determine the range of vibrational frequencies associated with Li ion motions which might contribute to the diffusion processes.

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Section: Formation Energies For Vacancy-interstitial Pairs Of Intsupporting

confidence: 73%

Mechanisms ofLi+diffusion in crystallineγ- andβ−Li3
Du
¹
,
Holzwarth
²

2007
Phys. Rev. B
99
5
51
0
View full text Add to dashboard Cite

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“…The simulations of the interstitialcy mechanism described here for diffusion within the type I void channels or for diffusion between type I and type II void channels suggest possible mechanisms for interstitial Li ion diffusion in all three crystallographic directions. The calculated migration energies of E m = 0.35 eV for the a-axis diffusion and E m = 0.21 eV for the b-or c-axis diffusion are considerably smaller than experiment 3,23,31,33 and smaller than the calculated barriers for the vacancy mechanisms.…”

Section: Resultsmentioning

confidence: 55%

“…Experimental measurements have shown that the Li ion conductivity of polycrystalline 3 and single crystal 23…”

Section: Calculational Methodsmentioning

confidence: 99%

Li Ion Diffusion Mechanisms in the Crystalline Electrolyte γ-Li[sub 3]PO[sub 4]

Holzwarth

2007

J. Electrochem. Soc.

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Solid state lithium ion electrolytes are becoming increasingly important in batteries and related technologies. We have used first-principles modeling techniques based on density functional theory and the nudged elastic band method to examine possible Li ion diffusion mechanisms in idealized crystals of the electrolyte material Li 3 PO 4. In modeling the Li ion vacancy diffusion, we find direct hopping between neighboring metastable vacancy configurations to have a minimal migration barrier of E m = 0.6 eV. In modeling the Li ion interstitial diffusion, we find an interstitialcy mechanism, involving the concerted motion of an interstitial Li ion and a neighboring Li ion of the host lattice, that can result in a migration barrier as low as E m = 0.2 eV. The minimal formation energy of a Li ion vacancy-interstitial pair is determined to be E f = 1.6 eV. Assuming the activation energy for intrinsic defects to be given by E A = E m + E f /2, the calculations find E A = 1.0-1.2 eV for ionic diffusion in crystalline ␥-Li 3 PO 4 , in good agreement with reported experimental values of 1.1-1.3 eV.

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“…The obtained activation energies are comparable to those for other lithium ion cathode compounds. 33,34 Given predominant electronic conductivity, the Li + diffusivity (D Li ) should have the form D Li ∝ σ ion (…”

Section: Resultsmentioning

confidence: 99%

Characterization of Electronic and Ionic Transport in Li_1-_xNi₀_.₈Co_0.15Al_0.05O₂(NCA)

Amin

Ravnsbæk

Chiang³

2015

J. Electrochem. Soc.

103

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Despite the extensive commercial use of Li 1-x Ni 0.8 Co 0.15 Al 0.05 O 2 (NCA) as the positive electrode in Li-ion batteries, and its long research history, its fundamental transport properties are poorly understood. These properties are crucial for designing high energy density and high power Li-ion batteries. Here, the transport properties of NCA are investigated using impedance spectroscopy and dc polarization and depolarization techniques. The electronic conductivity is found to increase with decreasing Li-content from ∼10 −4 Scm −1 to ∼10 −2 Scm −1 over x = 0.0 to 0.6, while lithium ion conductivity is at least five orders of magnitude lower for x = 0.0 to 0.75. A surprising result is that the lithium ionic diffusivity vs. x shows a v-shaped curve with a minimum at x = 0.5, while the unit cell parameters show the opposite trend. This suggests that cation ordering has greater influence on the composition dependence than the Li layer separation, unlike other layered oxides. From temperature-dependent measurements in electron-blocking cells, the activation energy for lithium ion conductivity (diffusivity) is found to be 1.25 eV (1.20 eV). Chemical diffusion during electrochemical use is limited by lithium transport, but is fast enough over the entire state-of-charge range to allow charge/discharge of micron-scale particles at practical C-rates. Cathodes having high energy and power density, adequate safety, excellent cycle life, and low cost are crucial for Li-ion batteries that can enable the commercialization of electric transportation.1 Towards this end, much research has previously focused on the development of the LiNi 1-x Co x O 2 (NC) 2-10 cathode due to its high capacity (∼275 mAh/g) and favorable operating cell voltage (4.3 V vs. Li/Li + ), which is within the voltage stability window of current liquid electrolytes. This compound also has lower cost than LiCoO 2 ; but despite extensive optimization, e.g., with respect to the Ni/Co ratio, 2-10 NC still suffers from poor structural stability during electrochemical cycling.11 Significant efforts were subsequently focused on improving structural stability by doping with small amounts of electrochemically inactive elements such as Al and Mg.12-17 One of the most promising compositions that emerged is Li 1 Ni 0.8 Co 0.15 Al 0.05 O 2 (NCA), currently in widespread commercial use. This intercalation material exhibits solid solution behavior during the extraction of lithium 3,4,18 and is structurally stable upon cycling. 2 The majority of studies of NCA have focused on structural and electrochemical characterization. Surprisingly, there is limited, and conflicting, data on the basic transport properties of the NC/NCA family of compounds. Thus our objective in this work is to systematically characterize and interpret the transport properties of NCA. We use additive-free, single phase sintered samples in which the extrinsic effects that may be present in composite electrodes are avoided. Using electron blocking and ion blocking cell configurations, respectively...

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Growth and ionic conductivity of γ-Li3PO4

Cited by 46 publications

References 5 publications

Mechanisms ofLi+diffusion in crystallineγ- andβ−Li3
Du
¹
,
Holzwarth
²

2007
Phys. Rev. B
99
5
51
0
View full text Add to dashboard Cite

Mechanisms ofLi+diffusion in crystallineγ- andβ−Li3
Du
¹
,
Holzwarth
²

2007
Phys. Rev. B
99
5
51
0
View full text Add to dashboard Cite

Li Ion Diffusion Mechanisms in the Crystalline Electrolyte γ-Li[sub 3]PO[sub 4]

Characterization of Electronic and Ionic Transport in Li_1-_xNi₀_.₈Co_0.15Al_0.05O₂(NCA)

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Growth and ionic conductivity of γ-Li3PO4

Cited by 46 publications

References 5 publications

Mechanisms ofLi+diffusion in crystallineγ- andβ−Li3Du1, Holzwarth2 2007Phys. Rev. B995510View full textAdd to dashboardCite

Mechanisms ofLi+diffusion in crystallineγ- andβ−Li3Du1, Holzwarth2 2007Phys. Rev. B995510View full textAdd to dashboardCite

Li Ion Diffusion Mechanisms in the Crystalline Electrolyte γ-Li[sub 3]PO[sub 4]

Characterization of Electronic and Ionic Transport in Li1-xNi0.8Co0.15Al0.05O2(NCA)

Contact Info

Product

Resources

About

Mechanisms ofLi+diffusion in crystallineγ- andβ−Li3
Du
¹
,
Holzwarth
²

2007
Phys. Rev. B
99
5
51
0
View full text Add to dashboard Cite

Mechanisms ofLi+diffusion in crystallineγ- andβ−Li3
Du
¹
,
Holzwarth
²

2007
Phys. Rev. B
99
5
51
0
View full text Add to dashboard Cite

Characterization of Electronic and Ionic Transport in Li_1-_xNi₀_.₈Co_0.15Al_0.05O₂(NCA)