Xn:Harmful;
554-13-2Relevant articles and documents
Changes of nitrides characteristics in Li-N system synthesized at different pressures
Ignatenko, Oleg V.,Komar, Valery A.,Leonchik, Sergey V.,Shempel, Natalia A.,Ene, Antoaneta,Cantaragiu, Alina,Frontasyeva, Marina V.,Shvetsov, Valery N.
, p. 23 - 27 (2013)
For the Li-N system samples were obtained at pressures of nitrogen from 1 to 10 atm. Energy-dispersive X-ray (EDX) spectrum of a sample of Li-N subjected to degradation shows that lithium nitride turned into carbonate as evidenced by the predominant content of carbon and oxygen. Upon synthesis of lithium nitride at a positive pressure of nitrogen, the b-modification is formed, which can be achieved at a pressure 500 times lower than that described in literature, required to create a high-pressure phase. The increase in carbon content with increasing of synthesis pressure of lithium nitride confirms the change in stoichiometry of its structure formed with high nitrogen content.
On the incompatibility of lithium-O2 battery technology with CO2
Zhang, Shiyu,Nava, Matthew J.,Chow, Gary K.,Lopez, Nazario,Wu, Gang,Britt, David R.,Nocera, Daniel G.,Cummins, Christopher C.
, p. 6117 - 6122 (2017)
When solubilized in a hexacarboxamide cryptand anion receptor, the peroxide dianion reacts rapidly with CO2 in polar aprotic organic media to produce hydroperoxycarbonate (HOOCO2-) and peroxydicarbonate (-O2COOCO2-). Peroxydicarbonate is subject to thermal fragmentation into two equivalents of the highly reactive carbonate radical anion, which promotes hydrogen atom abstraction reactions responsible for the oxidative degradation of organic solvents. The activation and conversion of the peroxide dianion by CO2 is general. Exposure of solid lithium peroxide (Li2O2) to CO2 in polar aprotic organic media results in aggressive oxidation. These findings indicate that CO2 must not be introduced in conditions relevant to typical lithium-O2 cell configurations, as production of HOOCO2- and -O2COOCO2- during lithium-O2 cell cycling will lead to cell degradation via oxidation of organic electrolytes and other vulnerable cell components.
A study of binary iron/lithium organometallic complexes as single source precursors to solid state cathode materials for potential Li ion battery application
Khanderi, Jayaprakash,Schneider, J?rg J.
, p. 254 - 259 (2011)
Solid state and solution phase decomposition of organometallic half sandwich and sandwich complexes of type [CpFeCODLi × DME] 1, [CpFeCODLi × TMEDA] 2 and [(Cp)2FeLi2 × 2 TMEDA] 3 (Cp = cyclopentadienyl, COD = 1,5-cyclooctadiene, DME = dimethoxyethane, TMEDA = tetramethylethylenediamine) derived from ferrocene, yield different kinds of lithium ferrites under oxidative and inert conditions. Thermogravimetry (TG) and TG coupled mass spectrometry of these compounds indicate that the decomposition begins above 170 °C for 1, 185 °C for 2 and 190 °C for 3 with removal of all the organic ligands. In the absence of oxygen, compounds 1, 2 and 3 decompose to a mixture of Fe, Fe3C and Li2O/Li 2CO3 at temperatures above 200 °C. Amorphous α-LiFeO2 is formed in the temperature range of 200-400 °C in the presence of oxygen. Crystalline α-LiFeO2 is formed only above 400 °C using 1. Elemental analysis of the LiFeO2 obtained from 1 indicates a drastic decrease in the carbon and hydrogen content with the increase in the oxidation temperature. XRD reveals the presence of Li 2CO3 as second phase formed for precursors 1, 2, and 3 under oxidative conditions. Solution phase decomposition of 2 and 3 in the absence of oxygen followed by annealing at 600 °C yields Li 2Fe3O5, Li5FeO4 and Fe3C depending on the solvent to precursor ratio in contrast to the α-LiFeO2 phase formed under pure solid state decomposition conditions. However, all lithium ferrites (Li2Fe3O 5, Li5FeO4) are converted to α-LiFeO 2 when oxidized above 500 °C. The α-LiFeO2 products were further characterized by IR, XPS, and TEM. Electrochemical analysis of the α-LiFeO2 was performed, showing a moderate initial capacity of 13 mAh/g.
Synthesis of Li4SiO4 by a modified combustion method
Cruz, Daniel,Bulbulian, Silvia
, p. 1720 - 1724 (2005)
We report for the first time the synthesis of Li4SiO4 by the modified combustion method, a rapid chemical process that takes 5 min for completion. This method uses nonoxidizer compounds instead of nitrate mixtures, which are not always commercially available. The effects of the following parameters on the production of Li4SiO4 were studied: (1) different lithium hydroxide:silicic acid:urea (LiOH:H 2SiO3:CH4N2O) molar ratios; (2) the presence of air flow in the furnace chamber; and (3) the furnace heating temperature. It was found that LiOH:H2SiO3:CH 4N2O molar ratios 6:1:3 heated at 1100°C in the presence of additional air in the muffle chamber formed the best precursors to produce Li4SiO4.
Characterization of Li1-xNi1+xO2 prepared using succinic acid as a complexing agent
Thongtem, Titipun,Thongtem, Somchai
, p. 202 - 209 (2006)
Li1-xNi1+xO2 was prepared by a polymerized complex method using succinic acid as a complexing agent. Ethanolic solutions of lithium acetate dihydrate, nickel acetate tetrahydrate, and succinic acid were mixed to form carboxylate precursors, which were subsequently calcined at 650-800°C for 14-48 h. TGA curves of metal acetates, succinic acid, and the precursors were characterized to determine weight loss and formation temperature of the oxide. By using XRD, SEM, and EDX, pure crystals of Li 1-xNi1+xO2 were detected at 750 and 800°C. The maximum and minimum intensity ratios of XRD spectra show that the optimum calcination condition is 750°C for 40 h. At 650-800°C, the particle size distribution is in the range of 0.35-39 μm. Pleiades Publishing, Inc., 2006.
Lithium silicate nanosheets with excellent capture capacity and kinetics with unprecedented stability for high-temperature CO2capture
Belgamwar, Rajesh,Maity, Ayan,Das, Tisita,Chakraborty, Sudip,Vinod, Chathakudath P.,Polshettiwar, Vivek
, p. 4825 - 4835 (2021)
An excessive amount of CO2is the leading cause of climate change, and hence, its reduction in the Earth's atmosphere is critical to stop further degradation of the environment. Although a large body of work has been carried out for post-combustion low-temperature CO2capture, there are very few high temperature pre-combustion CO2capture processes. Lithium silicate (Li4SiO4), one of the best known high-temperature CO2capture sorbents, has two main challenges, moderate capture kinetics and poor sorbent stability. In this work, we have designed and synthesized lithium silicate nanosheets (LSNs), which showed high CO2capture capacity (35.3 wt% CO2capture using 60% CO2feed gas, close to the theoretical value) with ultra-fast kinetics and enhanced stability at 650 °C. Due to the nanosheet morphology of the LSNs, they provided a good external surface for CO2adsorption at every Li-site, yielding excellent CO2capture capacity. The nanosheet morphology of the LSNs allowed efficient CO2diffusion to ensure reaction with the entire sheet as well as providing extremely fast CO2capture kinetics (0.22 g g?1min?1). Conventional lithium silicates are known to rapidly lose their capture capacity and kinetics within the first few cycles due to thick carbonate shell formation and also due to the sintering of sorbent particles; however, the LSNs were stable for at least 200 cycles without any loss in their capture capacity or kinetics. The LSNs neither formed a carbonate shell nor underwent sintering, allowing efficient adsorption-desorption cycling. We also proposed a new mechanism, a mixed-phase model, to explain the unique CO2capture behavior of the LSNs, using detailed (i) kinetics experiments for both adsorption and desorption steps, (ii)in situdiffuse reflectance infrared Fourier transform (DRIFT) spectroscopy measurements, (iii) depth-profiling X-ray photoelectron spectroscopy (XPS) of the sorbent after CO2capture and (iv) theoretical investigation through systematic electronic structure calculations within the framework of density functional theory (DFT) formalism.
Synthesis and CO2 adsorption characteristics of lithium zirconates with high lithia content
Yin, Xian-Sheng,Li, Shao-Peng,Zhang, Qin-Hui,Yu, Jian-Guo
, p. 2837 - 2842 (2010)
Pure monoclinic phase Li6Zr2O7 and rhombohedral phase Li8ZrO6 that coexisted with a fraction of Li6Zr2O7, are synthesized by a liquid phase coprecipitation method and characterized by X-ray diffraction, scanning electron microscopy, and thermo-gravimetric analysis. The high-temperature CO 2 uptake properties of both samples are systematically investigated. The temperature effect tests indicate that, in the case of low temperature (2 uptake rates because of the inhibited diffusion of CO2 in the solid carbonate shell; while at the temperature above the melting point of Li2CO 3 (about 983 K), the CO2 uptake rates are enhanced dramatically for both Li6Zr2O7 and Li 8ZrO6, and achieved about 12.3% weight gain and 35.0% weight gain within 15 min at 1073 K, respectively. The thermal stability tests indicate that both samples exhibit gradually reduced capacities during the multicycle processes. The analysis of the crystalline structure reveals that the reduced capacities are resulted from the loss of lithia under high temperatures. Finally, the possible adsorption pathways for both monoclinic phase Li6Zr2O7 and rhombohedral phase Li 8ZrO6 are suggested as well.
Electrochemical Decomposition of Li4SiO4 and Li2TiO3 in Solid-state Thermal Cells
Aceves, Juan M.,West, Anthony R.
, p. 2599 - 2608 (1982)
Cells of the type Au/Li4SiO4/Au and Au/Li2TiO3/Au behave as secondary cells at high temperatures, >/=400 deg C.The cell reactants are created in situ by charging the cells in air at e.g. 1.5 V.Electrochemical decomposition of the solid electrolytes occurs giving, as solid products, Li2CO3 at the negative electrode and Li2SiO3 and TiO2, respectively, at the positive electrode.Under different charging conditions other products may be obtained with the Li2TiO3-containing cell.The products of charging form as a layer on the surfaces of the pellet and the gold electrodes appear to take no part in the reactions.The charged cells have open-circuit voltages in the range 0.4 - 0.5 V at ca. 500 deg C and give discharge currents of e.g. 10 - 100 μA through a 10E4 Ω load resistance for several days.
Evidence of CO2 chemisorption at high temperature in lithium Gallate (Li5GaO4)
Avalos-Rendon, Tatiana,Pfeiffer, Heriberto
, p. 504 - 505 (2011)
Li5GaO4 was tested as a possibleCO2 captor. Li5GaO4 was synthesized by solid-state reaction, structurally characterized, and then thermally treated under a CO2 flow, from 30 to 900 °C, having the highest CO2 chemisorption at around 709 °C. The results clearly showed that Li5GaO4 isable to trap CO2 chemically in two different steps. The CO2 quantity trapped was equal to 8.9 mmol g-1, which is considerablyhigh in comparison to other ceramics.
Thermally driven interfacial degradation between Li7La3Zr2O12 electrolyte and LiNi0.6Mn0.2Co0.2O2 cathode
Kim, Younggyu,Kim, Dongha,Bliem, Roland,Vardar, Gülin,Waluyo, Iradwikanari,Hunt, Adrian,Wright, Joshua T.,Katsoudas, John P.,Yildiz, Bilge
, p. 9531 - 9541 (2020)
Solid-state batteries offer higher energy density and enhanced safety compared to the present lithium-ion batteries using liquid electrolytes. A challenge to implement them is the high resistances, especially at the solid electrolyte interface with the cathode. Sintering at elevated temperature is needed in order to get good contact between the ceramic solid electrolyte and oxide cathodes and thus to reduce contact resistances. Many solid electrolyte and cathode materials react to form secondary phases. It is necessary to find out which phases arise as a result of interface sintering and evaluate their effect on electrochemical properties. In this work, we assessed the interfacial reactions between LiNi0.6Mn0.2Co0.2O2 (NMC622) and Li7La3Zr2O12 (LLZO) as a function of temperature in air. We prepared model systems by depositing thin-film NMC622 cathode layers on LLZO pellets. The thin-film cathode approach enabled us to use interface-sensitive techniques such as X-ray absorption spectroscopy in the near-edge as well as the extended regimes and identify the onset of detrimental reactions. We found that the Ni and Co chemical environments change already at moderate temperatures, on-setting from 500 °C and becoming especially prominent at 700 °C. By analyzing spectroscopy results along with X-ray diffraction, we identified Li2CO3, La2Zr2O7, and La(Ni,Co)O3 as the secondary phases that formed at 700 °C. The interfacial resistance for Li transfer, measured by electrochemical impedance spectroscopy, increases significantly upon the onset and evolution of the detected interface chemistry. Our findings suggest that limiting the bonding temperature and avoiding CO2 in the sintering environment can help to remedy the interfacial degradation.
