Movement Of Lithium Ions Research Articles

Muon spectroscopy for studying magnetism and protons and lithium dynamics in spinel manganese oxides

Polarised positive muons can be implanted into any type of material and rapidly thermalize, then the local magnetic environment dictates the evolution of muon spin vectors and provokes the muon depolarisation. The muon spin relaxation (μSR) technique provides interesting information on magnetism and spin dynamics in spinel lithium manganates insertion compounds. In this work, we compare the behaviour of muons into a lithium-rich spinel manganese oxide and its lithium extracted product. The chemical extraction of lithium from Li 1.33Mn 1.67O 4, where all the manganese is Mn IV, is essentially a lithium by proton ion exchange process to give a protonated manganese oxide with spinel structure, H +–MnO 2. Muons clearly have showed the presence of protons in H +–MnO 2, and the movement of lithium ions or protons at increasing temperatures in both samples. Muons are quasi-static in these compounds, and they are located both in ‘regular’ lithium and proton sites and also in interstitial sites of the spinel structure, these latter being used during diffusion of lithium ions. Below 50 K, static muons behave as in a paramagnet, where Mn magnetic spins are slowing down and ordering near 6 and 14 K in the protonated and lithiated spinels, respectively.

Muon Spin Relaxation Study of Spinel Lithium Manganese Oxides

The muon spin relaxation technique has been used to study spinel lithium manganate insertion compounds. Two spinel compositions of lithium manganese oxide have been studied: mixed valence (MnIII/MnIV) LiMn2O4, where the lithium extraction process is mainly by redox reaction, and Li1.33Mn1.67O4, where all the manganese is MnIV and lithium extraction is a lithium by proton ion exchange. Extraction of lithium from the former gives a spinel manganese oxide without lithium or protons (λ-MnO2), while from the latter a protonated manganese oxide is obtained (H+-MnO2). Muons are quasi-static in these compounds, and they are located both in “regular” lithium and proton sites and in interstitial sites of the spinel structure, these latter being used during diffusion of lithium ions and protons. Results clearly reflect the presence of protons in H+-MnO2 and the movement of lithium ions in both lithium manganates. The lithium-rich phase Li1.33Mn1.67O4 is characterized by an increase of the number of implanted muons localized in interstitial sites, as well as by a decrease of the onset temperature for lithium diffusion.

On the Mechanism of Ion Transport through Polyphosphazene Solid Polymer Electrolytes: NMR, IR, and Raman Spectroscopic Studies and Computational Analysis of 15N-Labeled Polyphosphazenes

Comprehensive investigation of lithium ion complexation with 15N-labeled polyphosphazenes 15N-poly[bis(2-(2-methoxyethoxy)ethoxy)phosphazene] (15N-MEEP) and 15N-poly-[((2-allylphenoxy)0.12(4-methoxyphenoxy)1.02(2-(2-methoxyethoxy)ethoxy)0.86)phosphazene] (15N-HPP)was performed by NMR, IR, and Raman spectroscopies. Previous studies characterized the ionic transport through the polymer matrix in terms of “jumps” between neighboring polymer strands utilizing the electron lone pairs of the etherial oxygen nuclei with the nitrogen nuclei on the polyphosphazene backbone not involved. However, noteworthy changes were observed in the NMR, IR, and Raman spectra with the addition of lithium trifluoromethanesulfonate (LiOTf) to the polyphosphazenes. The data indicate that the preferred association for the lithium ion with the polymer is with the nitrogen nuclei, resulting in the formation of a “pocket” with the pendant groups folding around the backbone. NMR temperature-dependent spin−lattice relaxation (T1) studies (13C, 31P, and 15N) indicate significant lithium ion interaction with the backbone nitrogen nuclei. These studies are in agreement with molecular dynamics simulations investigating lithium ion movement within the polyphosphazene matrix.

Relaxation mechanisms and microstructure in glass and glass-ceramics

Two LAS (Li 2O–Al 2O 3–SiO 2)-type glass-ceramics and their parent glass have been studied by isothermal mechanical spectroscopy. These materials have the same chemical composition but the two glass-ceramics differ in microstructure: one is a ‘β-quartz’ glass-ceramic whereas the other one is of ‘β-spodumene’ type. The isothermal internal friction measurements performed in a frequency sweep [10 −4–31.6 Hz] with an inverted torsion pendulum, submitted to subresonant forced oscillations, at temperatures between 93 and 820 K, have revealed several mechanical relaxation peaks. A single internal friction peak is observed in the glass sample whereas two peaks occur in the ‘β-quartz’ and ‘β-spodumene’ glass-ceramics. A detailed microstructure analysis (XRD, IRTF, SEM, TEM and DTA) and dielectric loss measurements have allowed to interpret these relaxation phenomena. The mechanical relaxation peak observed in the glass (∼290 K for 1 Hz) is assigned to the stress-induced movement of lithium ions. In each glass-ceramic the ‘low-temperature’ peak (∼340 K for 1 Hz) is linked with the ion mobility in the respective main crystalline phase. As for the ‘high-temperature’ peak, its origin is totally different for the two glass-ceramics; in the ‘β-quartz’ glass-ceramic it is due to the Mg 2+ and Zn 2+ ion relaxation in the crystalline phase, whereas in the ‘β-spodumene’ glass-ceramic it is linked with a complex entity within the residual vitreous phase.

Mechanical relaxations in LAS-type glass and glass-ceramics related with microstructure

Mechanical relaxation phenomena have been studied on two Li 2 O-Al 2 O 3 -SiO 2 -type glass-ceramics and their parent glass by isothermal mechanical spectrometry. These materials have the same chemical composition but the two glass-ceramics differ in microstructure: one is of β-quartz type whereas the other one is of β-spodumene type. The internal friction measurements have shown several mechanical relaxation peaks. These relaxation effects have been interpreted from dielectric loss measurements and microstructure analysis (SEM, TEM, FTIR, XRD and DTA). For the glass, a single mechanical relaxation peak occurs: it is linked with the stress-induced movement of lithium ions. Contrary to the glass, two internal friction peaks are observed in the β-quartz and β-spodumene glass-ceramics. The low-temperature peak is assigned to the ion mobility in the respective main crystalline phase. For each glass-ceramic, the high-temperature peak is due to different relaxation mechanisms. In the β-quartz glass-ceramic, it is assigned to Mg 2+ and Zn 2+ ion relaxation in the crystalline phase, whereas in the β-spodumene glass-ceramic, it is linked with a complex entity within the residual vitreous phase.

Nr Measurements to Study The Reversible Transfer of Lithium Ion in Lithium Titanium Oxide

ABSTRACTUsing Neutron Radiography (NR), the transfer of lithium ions has been investigated in the high temperature-type lithium ion conductor, Li1.33Ti1.67O4. After supplying direct current to the oxides with different isotope ratios (6Li/7Li), NR images were obtained, which confirmed lithium ion movement in the oxides as changes of bright parts on negative films. Analysis of the NR images clarified that lithium ions in the spinel-type Li1.33Ti1.67O4were transported almost reversibly according to the polarity of electric field applied. The relations between the lithium contents in the samples and the film gray level showed that the cathode region in the charged sample contains about twice more lithium than in the original sample. Furthermore, NR method was applied to check lithium ion insertion into the TiO2(rutile) sample. As a result, an informative Neutron Radiogram showing the lithium ion insertion was obtained.

Alkali ion conduction in the substituted phase based on the scheelite-type oxide

The ionic conductivity of substituted CaWO 4 phase was investigated by electrochemical methods. Substitution by lithium as Ca 1 − x Li 2 x WO 4 to increase the concentration of interstitial ions enhanced the ionic conductivity. The charge carrier in that phase was lithium ion. The movement of lithium ion was visualized by neutron radiography.

Application of NR for research in electrochemical systems

The neutron radiography (NR) technique has been applied to high temperature ion conducting materials such as Li 1.33 Ti 1.67O 4 and Ca 0.95 Li 0.1 WO 4 in order to visualize the movement of lithium ions within the material. After electrolysis DC current was passed through these oxides prepared with different isotope ratios ( 6Li/ 7Li), a set of NR images was obtained which verified the lithium ion conduction in the oxides. It was also clearly shown that the transport number of lithium ions in such oxides can be accurately determined by digitizing and analyzing the NR images. In addition, some investigation was carried out using the NR technique to see the lithium distribution in a lithium battery before and after discharge. The results indicated that NR can be used to clarify the local discharging efficiency in a battery and/or to investigate the reversibility of lithium rechargeable batteries.

Application of Neutron Radiography to Visualize the Motion of Lithium Ions in Lithium‐Ion Conducting Materials

Neutron radiography (NR) has been applied to a lithium in conducting spinel‐type oxide in order to visualize the movement of lithium ions. After dc current was passed for electrolysis through specially prepared oxides with different isotope ratios , a set of NR images was obtained that illustrate the lithium ion conduction in the oxide. Analysis of the NR images determined that the transport number of lithium ions in the spinel‐type is 0.99 at 900°C, which is almost the same as that measured by the oxygen concentration cell method. Further detailed analysis was carried out to investigate which kind of lithium ion in the oxide ion array of the spinel‐type structure contributes to the electric conduction, the tetrahedral A site lithium, the octahedral B site, or both of these. As a result, the contribution of A site lithium to ionic conduction was confirmed.

Lithium Ion Conductivity of A‐Site Deficient Perovskite Solid Solution La0.67 − xLi3xTiO3

solid solution forms in the range by the substitution mechanism . Superstructure reflections observed in this range are consistent with a superlattice consisting of the stacking of two perovskite subcells. A line‐splitting phenomenon observed for indicates that the tetragonal distortion of the cubic perovskite subcell occurs. The solid solutions exhibit high lithium ion conductivities greater than 10−4 S cm−1 at room temperature in a wide range, . A maximum conductivity of is found at . The dome‐shaped composition dependence of conductivity indicates that the conduction mechanism involves the movement of lithium ions through the A‐site vacancies.

Lithium-ion mobility improvement in floating-zone silicon by external gettering

Phosphorous diffusion for approximately 1 h at 950 °C is shown to be an effective gettering procedure to remove lithium-ion mobility reducing defects in floating-zone p-type silicon wafers. The removal of these defects, which can severely impede the movement of lithium ions in silicon wafers during lithium-ion compensation process, is crucial in the fabrication of silicon lithium-drifted radiation detectors.

Plasma and brain lithium levels after lithium carbonate and lithium chloride administration by different routes in rats.

SummaryA study of the absorption and distribution of lithium carbonate and lithium chloride after oral and ip administration has shown that lithium chloride was absorbed more rapidly into the blood than lithium carbonate after ip administration, that lithium chloride given orally is absorbed to a lesser extent than lithium carbonate, and that the patterns of oral and ip absorption of both compounds are similar. We have also shown that the movement of lithium ions into the brain is slow, that only relatively low levels are achieved, and that the lithium brain levels are directly related to and dependant on the magnitude and duration of the plasma levels.