Lithium Isotope Effect Accompanying Electrochemical Intercalation of Lithium into Graphite

2003 ◽  
Vol 58 (5-6) ◽  
pp. 306-312 ◽  
Author(s):  
Satoshi Yanase ◽  
Wakana Hayama ◽  
Takao Oi
Keyword(s):  
Isotope Effect ◽  
Separation Factor ◽  
Early Stage ◽  
Isotope Separation ◽  
Ethylene Carbonate ◽  
Lithium Ion ◽  
Lithium Isotope ◽  
Mixed Solution ◽  
Electrochemical Intercalation ◽  
Graphite Intercalation

Lithium has been electrochemically intercalated from a 1:2 (v/v) mixed solution of ethylene carbonate (EC) and methylethyl carbonate (MEC) containing 1 M LiClO4 into graphite, and the lithium isotope fractionation accompanying the intercalation was observed. The lighter isotope was preferentially fractionated into graphite. The single-stage lithium isotope separation factor ranged from 1.007 to 1.025 at 25 °C and depended little on the mole ratio of lithium to carbon of the lithium-graphite intercalation compounds (Li-GIC) formed. The separation factor inceased with the relative content of lithium. This dependence seems consistent with the existence of an equilibrium isotope effect between the solvated lithium ion in the EC/MEC electrolyte solution and the lithium in graphite, and with the formation of a solid electrolyte interfaces on graphite at the early stage of intercalation.

Lithium Isotope Effect Accompanying Electrochemical Insertion of Lithium into Liquid Gallium

2010 ◽  
Vol 65 (5) ◽  
pp. 461-467 ◽  
Author(s):  
Keita Zenzai ◽  
Ayaka Yasui ◽  
Satoshi Yanase ◽  
Takao Oi
Keyword(s):  
Isotope Effect ◽  
Isotope Effects ◽  
Isotope Separation ◽  
Ethylene Carbonate ◽  
Quantitative Agreement ◽  
Liquid Gallium ◽  
Molecular Orbital Calculations ◽  
Lithium Isotope ◽  
Mixed Solution ◽  
Separation Factors

Lithium was electrochemically inserted from a 1 : 2 (v/v) mixed solution of ethylene carbonate (EC) and methylethyl carbonate (MEC) containing 1M LiClO4 into liquid gallium to observe lithium isotope effects accompanying the insertion. It was observed that the lighter isotope 6Li was preferentially fractionated into liquid gallium with the single-stage lithium isotope separation factors S, ranging from 1.005 to 1.031 at 50 °C and 1.003 to 1.024 at 25 °C. The lithium isotope effects estimated by molecular orbital calculations at the B3LYP/6-311G(d) level of theory agreed qualitatively with those of the experiments, but the quantitative agreement of the two was not satisfactory

Estimation of Reduced Partition Function Ratios of Lithium-Graphite Intercalation Compounds by Density Functional Theory

2014 ◽  
Vol 69 (3-4) ◽  
pp. 122-128 ◽  
Author(s):  
Kunihiko Sato ◽  
Shun Saito ◽  
Satoshi Yanase ◽  
Takao Oi
Keyword(s):  
Partition Function ◽  
Density Functional ◽  
Ethylene Carbonate ◽  
Lithium Ion ◽  
Intercalation Compounds ◽  
Lithium Isotope ◽  
Graphite Intercalation Compounds ◽  
Isotope Exchange Reaction ◽  
Graphite Intercalation ◽  
Lithium Graphite

The reduced partition function ratio (RPFR) of lithium in lithium-graphite intercalation compounds (Li-GICs) was evaluated at the UB3LYP=6-311G(d) level of theory. The partition functions were written in the usual rigid-rotor harmonic oscillator approximation.With a C24H12 coronene molecule as the model of graphene, lithium-coronene sandwich, and club sandwich compounds were considered as models of Li-GICs. The estimated value of the 6Li-to-7Li RPFR was 1.0402 at 25 °C, which yielded 1.034 as the value of the equilibrium constant, K, of the lithium isotope exchange reaction between a lithium ion in an ethylene carbonate=ethylmethyl carbonate mixed solvent and a lithium atom in interlayer space of graphite. The estimated value of K was larger than the experimental value of 1.025. The unsatisfactory agreement between the estimated and experimental K values suggested that larger molecules should be used as models of graphene and that the vibrational anharmonicity should also be taken into consideration.

Lithium Isotope Effect Accompanying Chemical Insertion of Lithium into Graphite

2002 ◽  
Vol 57 (11) ◽  
pp. 857-862 ◽  
Author(s):  
Satoru Hashikawa ◽  
Satoshi Yanase ◽  
Takao Oi
Keyword(s):  
Separation Factor ◽  
Isotope Fractionation ◽  
Isotope Separation ◽  
Lithium Isotope ◽  
Graphite Phase ◽  
Graphene Layers ◽  
Surface Areas ◽  
Graphite Intercalation ◽  
Factor Data ◽  
Lithium Graphite

Lithiumwas chemically intercalated from 1-methoxybutane solution of lithiumand naphthalene into graphite and vice versa, and lithium isotope fractionation accompanying those intercalation and deintercalation processes was observed. 6Li was always preferentially fractionated into the graphite phase. The single-stage lithium isotope separation factor upon intercalation was about 1.023 at 25 ºC, nearly independent of the structure of the lithium-graphite intercalation compounds formed. A much smaller separation factor was observed for the deintercalation process, suggesting the existence of lithium sites (surface areas) other than the sites between graphene layers of the host graphite. Separation factor data were consistent with the following decreasing order of the 6Li-to-7Li reduced partition function ratio (RPFR): RPFR of 1-methoxybutane solution > RPFR of surface areas > RPFR of metal lithium > RPFR of graphene interlayer sites.

Electrochemical Isotope Effect and Lithium Isotope Separation

2009 ◽  
Vol 131 (29) ◽  
pp. 9904-9905 ◽  
Author(s):  
Jay R. Black ◽  
Grant Umeda ◽  
Bruce Dunn ◽  
William F. McDonough ◽  
Abby Kavner
Keyword(s):  
Isotope Effect ◽  
Isotope Separation ◽  
Lithium Isotope

Lithium Isotope Effects in Cation Exchange Chromatography of Lithium Lactate in Water-Dimethyl Sulfoxide and Water-Acetone Mixed Solvent Media

1993 ◽  
Vol 48 (7) ◽  
pp. 811-818
Author(s):  
Takao Oi ◽  
Akiko Kondoh ◽  
Etsuko Ohno ◽  
Morikazu Hosoe
Keyword(s):  
Dimethyl Sulfoxide ◽  
Mixed Solvent ◽  
Isotope Effects ◽  
Isotope Separation ◽  
Lithium Ion ◽  
External Solution ◽  
Exchange Chromatography ◽  
Lithium Isotope ◽  
Isotope Distributions ◽  
Lithium Lactate

Abstract Lithium isotope separation by ion exchange displacement chromatography of lithium lactate in water-dimethyl sulfoxide (DMSO) and water-acetone mixed solvent media at 25 °C was explored. In both the water-DMSO and water-acetone system, the single stage isotope separation factor (S) was a convex function of the mixing ratio of the solvents in the external solution phase; S had its maximum value of 1.00254 at water: DMSO = 25:75 v/v and 1.00182 at water: acetone = 75:25 v/v. Strong correlations of S with solvent partitions between the solution and the exchanger phases were found in both systems, which was qualitatively explainable by considering the lithium isotope distributions between the two phases based on the fundamental lithium isotope effects and the relative affinities of water, DMSO and acetone towards the lithium ion.

scholarly journals Electromigration Separation of Lithium Isotopes: The Effect of Electrode Solutions

2022 ◽  
Author(s):  
Ciming Wang ◽  
Pengrui Zhang ◽  
Chaochi Huang ◽  
Qian Zhang ◽  
Huiqun Ju ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Isotope Separation ◽  
Lithium Ion ◽  
Nuclear Industry ◽  
Lithium Isotope ◽  
Lithium Ions ◽  
Lithium Isotopes ◽  
Electrode Solutions ◽  
Organic Solutions

Abstract Both lithium-6 and lithium-7 with high abundance are indispensable materials in nuclear industry. Here, an aqueous solution│organic solution│aqueous solution system was fabricated to separate lithium isotopes. The effects of species and concentration of electrolytes in the electrode solutions on the lithium ions migration and lithium isotope separation with different voltages and migration time was studied. It was found that lithium-7 was enriched in aqueous solutions on both sides at 0 V and 2 V, while lithium-7 was enriched in anode solution and lithium-6 was enriched in cathode solution at 16 V. The weakening stability of the chelate consisted of crown ether and lithium ion with increasing voltage was believed to the possible reason. Meanwhile, the variation of electrolyte in electrode solution led to notable changes in migration ratio of lithium ions and lithium isotope separation effect, which can be attributed to the different degree of both ionization and hydrolysis for various electrolytes in aqueous solutions and the different ability of H+ and NH4+ to replace Li+ of chelate in organic solutions. This work is of great significance for the selection of electrode solutions in electromigration separation of lithium isotopes and even other electrochemical systems.

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