High-Pressure Melt Curve and Phase Diagram of Lithium

Frost, Mungo; Kim, Jongjin B.; McBride, E. E.; Peterson, James R.; Smith, Jesse S.; Sun, Peihao; Glenzer, S. H.

doi:10.1103/physrevlett.123.065701

“…Pressure was determined to an uncertainty of via the temperature adjusted equation of state 37 of a small quantity of tungsten powder (Alfa Aesar, 99.9%) added to each loading. Tungsten was chosen as it is known not to react with lithium 4 , 30 , and does not form hydrides below 25 GPa 9 . Powdered palladium (Alfa Aesar, 99.95%) was added to each cell such that the lithium would be in large excess.…”

Section: Methodsmentioning

confidence: 99%

The high-pressure lithium–palladium and lithium–palladium–hydrogen systems

Frost

¹

,

McBride

²

,

Smith

³

et al. 2022

Sci Rep

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The lithium–palladium and lithium–palladium–hydrogen systems are investigated at high pressures at and above room temperature. Two novel lithium–palladium compounds are found below $${18.7}\,{\mathrm{GPa}}$$ 18.7 GPa . An ambient temperature phase is tentatively assigned as $$F{\bar{4}}3m\,\hbox {Li}_{17}\hbox {Pd}_{4}$$ F 4 ¯ 3 m Li 17 Pd 4 , with $$a = 17.661(1)$$ a = 17.661 ( 1 ) Å at 8.64 GPa, isostructural with $$\hbox {Li}_{17}\hbox {Sn}_{4}$$ Li 17 Sn 4 . The other phase occurs at high-temperature and is $$I{\bar{4}}3m\, \hbox {Li}_{11}\hbox {Pd}_{2}$$ I 4 ¯ 3 m Li 11 Pd 2 , $$a = 9.218(1)$$ a = 9.218 ( 1 ) Å at 3.88 GPa and 200 $$^\circ {\mathrm{C}}$$ ∘ C , similar to $$\hbox {Li}_{11}\hbox {Pt}_{2}$$ Li 11 Pt 2 , which is also known at high pressure. The presence of hydrogen in the system results in an $$I{\bar{4}}3m$$ I 4 ¯ 3 m structure with $$a = 8.856(1)$$ a = 8.856 ( 1 ) Å at 9.74 GPa. This persists up to $${13.3}\,\mathrm{GPa}$$ 13.3 GPa , the highest pressure studied. Below $${2}\,{\mathrm{GPa}}$$ 2 GPa an fcc phase with a large unit cell, $$a = 19.324(1)$$ a = 19.324 ( 1 ) Å at 0.39 GPa, is also observed in the presence of hydrogen. On heating the hydrogen containing system at 4 GPa the $$I{\bar{4}}3m$$ I 4 ¯ 3 m phases persists to the melting point of lithium. In both systems melting the lithium results in the loss of crystalline diffraction from palladium containing phases. This is attributed to dissolution of the palladium in the molten lithium, and on cooling the palladium remains dispersed.

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“…Frost et al performed hightemperature dynamic compression across the melting of lithium employing a diamond anvil cell coupled with a gas membrane. 22 Lithium damage to the anvil culets had restricted the P/T-conditions achieved in previous experimental studies. Frost et al extended the experimental conditions at which lithium had been studied and argued that fast compression permits the experiment to be conducted on a shorter timescale than that of lithium-induced diamond anvil failure.…”

Section: Articlementioning

confidence: 99%

A resistively-heated dynamic diamond anvil cell (RHdDAC) for fast compression x-ray diffraction experiments at high temperatures

Méndez

¹

,

Marquardt

²

,

Husband

³

et al. 2020

Review of Scientific Instruments

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A resistively-heated dynamic diamond anvil cell (RHdDAC) setup is presented. The setup enables the dynamic compression of samples at high temperatures by employing a piezoelectric actuator for pressure control and internal heaters for high temperature. The RHdDAC facilitates the precise control of compression rates and was tested in compression experiments at temperatures up to 1400 K and pressures of ∼130 GPa. The mechanical stability of metallic glass gaskets composed of a FeSiB alloy was examined under simultaneous high-pressure/high-temperature conditions. High-temperature dynamic compression experiments on H 2 O ice and (Mg, Fe)O ferropericlase were performed in combination with time-resolved x-ray diffraction measurements to characterize crystal structures and compression behaviors. The employment of high brilliance synchrotron radiation combined with two fast GaAs LAMBDA detectors available at the Extreme Conditions Beamline (P02.2) at PETRA III (DESY) facilitates the collection of data with excellent pressure resolution. The pressure-temperature conditions achievable with the RHdDAC combined with its ability to cover a wide range of compression rates and perform tailored compression paths offers perspectives for a variety of future experiments under extreme conditions.

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“…The melting curve of Li shows a complex behavior. − The melting temperature of bcc-Li first increases with increasing pressure up to ∼7 GPa. Then the melting curve of bcc-Li becomes nearly pressure independent at pressures of 7–9 GPa.…”

Section: Introductionmentioning

confidence: 99%

“…Above 9 GPa in the stability field of fcc-Li, its melting curve displays a strong positive slope first and then a turnover to a negative slope up to 40 GPa. At higher pressures, the melting curve is observed to turnover again to a positive slope in the stability fields of phases with more complex structures. − It is interesting to note that the slope of the melting curve can change or even turn over within the stability field of a single solid phase. Considering that a liquid may exhibit different local orderings, , the slope changes in the melting curve may suggest possible structural changes in liquid Li under high pressure.…”

Section: Introductionmentioning

confidence: 99%

Structural Changes in Liquid Lithium under High Pressure

Shu

¹

,

Kono

²

,

Ohira

³

et al. 2020

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We have experimentally studied the effect of compression on the structure of liquid lithium (Li) by multiangle energy dispersive X-ray diffraction in a large-volume cupped-Drickamer-Toroidal cell. The structure factors, s(q), of liquid Li have been successfully determined under an isothermal compression at 600 ± 30 K and at pressures up to 11.5 GPa. The first peak position in s(q) is found to increase with increasing pressure and is showing an obvious slope change starting at ∼7.5 GPa. The slope change is interpreted as a structural change from bcc-like to fcc-like local ordering in liquid Li. At pressures above 8.7 GPa, the liquid Li becomes predominantly fcc-like up to the highest pressure of 11.5 GPa in this study. The observed structural changes in liquid Li are consistent with the recently determined melting curve of Li.

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High-Pressure Melt Curve and Phase Diagram of Lithium

Cited by 21 publications

References 31 publications

The high-pressure lithium–palladium and lithium–palladium–hydrogen systems

The high-pressure lithium–palladium and lithium–palladium–hydrogen systems

A resistively-heated dynamic diamond anvil cell (RHdDAC) for fast compression x-ray diffraction experiments at high temperatures

Structural Changes in Liquid Lithium under High Pressure

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