On the presence of a hydrous component in a gemstone variety of intermediate olivine-type triphylite-lithiophilite, Li(Fe,Mn)PO4

Libowitzky, Eugen; Beran, A.; Wieczorek, Arkadiusz K.; Wirth, Richard

doi:10.1007/s00710-012-0195-9

Cited by 9 publications

(6 citation statements)

References 33 publications

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“…Energy-dispersive system (EDS) elemental distribution maps reveal (b) depletion of P and (c) enrichment of Fe in a lamella compared to the host phase. Reprinted with permission from ref . Copyright 2012 Springer Verlag.…”

Section: Olivinesmentioning

confidence: 99%

“…14 These minerals are formed in nature by hydrothermal reactions. Naturally occurring single crystals of Li[FeMn]PO 4 have been found to contain micron-size inclusions of sarcopside, as well as protons 15 as indicated in Figure 2. In 1981 Belov et al 16 reported the formation of LiFePO 4 under hydrothermal conditions close to the physicochemical conditions of phosphate mineral formation in nature, 400 °C and 968 atm for 100 h.…”

Section: Olivines 21 Occurrence and Synthesismentioning

confidence: 99%

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Ultimate Limits to Intercalation Reactions for Lithium Batteries

2014

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Section: Olivinesmentioning

confidence: 99%

Section: Olivines 21 Occurrence and Synthesismentioning

confidence: 99%

Ultimate Limits to Intercalation Reactions for Lithium Batteries

2014

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“…The XO 4 3– → 4OH – substitution is well-known in the silicate minerals formed under hydrothermal conditions . This type of replacement gives rise to hydrogarnets (hydroxylated calcium aluminum silicates) , and humite-type defects in olivines n (Mg,Fe) 2 SiO 4 · m Mg 2 □ Si (OH) 4 (□vacancy). , On the basis of the IR spectra, the presence of a hydrous component in the natural triphylite was assumed to be partially associated with P vacancies . However, to our knowledge, the replacement of PO 4 3– by hydroxyl groups has never been considered in the context of defect chemistry of LiFePO 4 as the Li-ion battery cathode.…”

Section: Resultsmentioning

confidence: 91%

“…46,47 On the basis of the IR spectra, the presence of a hydrous component in the natural triphylite was assumed to be partially associated with P vacancies. 48 However, to our knowledge, the replacement of PO 4 3− by hydroxyl groups has never been considered in the context of defect chemistry of LiFePO 4 as the Li-ion battery cathode. Thus, we have performed density functional theory computations to estimate the energetics of the substituted phase, understand the location and bonding of protons and their influence on the crystal structure and Li diffusion barriers.…”

Section: Chemistry Of Materialsmentioning

confidence: 99%

“Hydrotriphylites” Li_1–xFe_1+x(PO₄)_1–_y(OH)_4y as Cathode Materials for Li-ion Batteries

et al. 2019

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Lithium iron phosphate LiFePO 4 triphylite is now one of the core positive electrode (cathode) materials enabling the Li-ion battery technology for stationary energy storage applications, which are important for broad implementation of the renewable energy sources. Despite the apparent simplicity of its crystal structure and chemical composition, LiFePO 4 is prone to offstoichiometry and demonstrates rich defect chemistry owing to variations in the cation content and iron oxidation state, and to the redistribution of the cations and vacancies over two crystallographically distinct octahedral sites. The importance of the defects stems from their impact on the electrochemical performance, particularly on limiting the capacity and rate capability through blocking the Li-ion diffusion along the channels of the olivine-type LiFePO 4 structure. Up to now, the polyanionic (i.e., phosphate) sublattice has been considered idle in this case. Here, we demonstrate that under hydrothermal conditions up to 16% of the phosphate groups can be replaced with hydroxyl groups yielding the Li 1−x Fe 1+x (PO 4 ) 1−y (OH) 4y solid solutions, which we term "hydrotriphylites". This substitution has a tremendous effect on the chemical composition and crystal structure of the lithium iron phosphate causing abundant population of the Li-ion diffusion channels with the iron cations and off-center Li displacements due to their tighter bonding to oxygens. These perturbations trigger the formation of an acentric structure and increase the activation barriers for the Li-ion diffusion. The hydrotriphylite-type substitution also affects the magnetic properties by progressively lowering the Neél temperature. The off-stoichiometry caused by this substitution critically depends on the overall concentration of the precursors and reducing agents in the hydrothermal solutions, placing it among the most important parameters to control the chemical composition and defect concentration of the LiFePO 4 -based cathodes.

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“…On the basis of the IR spectra the presence of a hydrous component in the natural triphylite was assumed to be partially associated with P vacancies. 48 However, to our knowledge, the replacement of PO 4 3by hydroxyl groups has never been considered in the context of defect chemistry of LiFePO 4 as the Li-ion battery cathode. Thus we have performed density functional theory computations to estimate the energetics of the substituted phase, understand the location and bonding of protons and their influence on the crystal structure and Li diffusion barriers.…”

mentioning

confidence: 99%

“Hydrotriphylites” Li1-xFe1+x(PO4)1-y(OH)4y as Cathode Materials for Li-ion Batteries

Sumanov¹,

Aksyonov²,

Drozhzhin³

et al. 2019

Preprint

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Lithium iron phosphate LiFePO4 triphylite is now one of the core positive electrode (cathode) materials enabling the Li-ion battery technology for stationary energy storage applications, which are important for broad implementation of the renewable energy sources. Despite the apparent simplicity of its crystal structure and chemical composition, LiFePO4 is prone to off-stoichiometry and demonstrates rich defect chemistry owing to variations in the cation content and iron oxidation state, and to the redistribution of the cations and vacancies over two crystallographically distinct octahedral sites. The importance of the defects stems from their impact on the electrochemical performance, particularly on limiting the capacity and rate capability through blocking the Li ion diffusion along the channels of the olivine-type LiFePO4 structure. Up to now the polyanionic (i.e. phosphate) sublattice has been considered idle on this playground. Here, we demonstrate that under hydrothermal conditions up to 16% of the phosphate groups can be replaced with hydroxyl groups yielding the Li1-xFe1+x(PO4)1-y(OH)4y solid solutions, which we term “hydrotriphylites”. This substitution has tremendous effect on the chemical composition and crystal structure of the lithium iron phosphate causing abundant population of the Li-ion diffusion channels with the iron cations and off-center Li displacements due to their tighter bonding to oxygens. These perturbations trigger the formation of an acentric structure and increase the activation barriers for the Li-ion diffusion. The “hydrotriphylite”-type substitution also affects the magnetic properties by progressively lowering the Néel temperature. The off-stoichiometry caused by this substitution critically depends on the overall concentration of the precursors and reducing agent in the hydrothermal solutions, placing it among the most important parameters to control the chemical composition and defect concentration of the LiFePO4-based cathodes.

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On the presence of a hydrous component in a gemstone variety of intermediate olivine-type triphylite-lithiophilite, Li(Fe,Mn)PO4

Abstract: hydrous point defects in the structure of triphylite and/or sarcopside, which are possible under the assumption of vacancies at the Li (M1) and/or P sites.

Cited by 9 publications

References 33 publications

Ultimate Limits to Intercalation Reactions for Lithium Batteries

Ultimate Limits to Intercalation Reactions for Lithium Batteries

“Hydrotriphylites” Li_1–xFe_1+x(PO₄)_1–_y(OH)_4y as Cathode Materials for Li-ion Batteries

“Hydrotriphylites” Li1-xFe1+x(PO4)1-y(OH)4y as Cathode Materials for Li-ion Batteries

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On the presence of a hydrous component in a gemstone variety of intermediate olivine-type triphylite-lithiophilite, Li(Fe,Mn)PO4

Abstract: hydrous point defects in the structure of triphylite and/or sarcopside, which are possible under the assumption of vacancies at the Li (M1) and/or P sites.

Cited by 9 publications

References 33 publications

Ultimate Limits to Intercalation Reactions for Lithium Batteries

Ultimate Limits to Intercalation Reactions for Lithium Batteries

“Hydrotriphylites” Li1–xFe1+x(PO4)1–y(OH)4y as Cathode Materials for Li-ion Batteries

“Hydrotriphylites” Li1-xFe1+x(PO4)1-y(OH)4y as Cathode Materials for Li-ion Batteries

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“Hydrotriphylites” Li_1–xFe_1+x(PO₄)_1–_y(OH)_4y as Cathode Materials for Li-ion Batteries