- REDUCTION OF CARBON DIOXIDE TO OXALATE BY LITHIUM ATOMS: A MATRIX ISOLATION STUDY OF THE INTERMEDIATE STEPS
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The codeposition of lithium atoms and carbon dioxide molecules in a krypton matrix at 9 K produces infrared absorptions attributable to five different species.Concentration effects, photosensitivity, annealing and isotopic substitutions provide information on the structure of each of these complexes, which have 1/1, 1/2 and 2/2 Li/CO2 stoichiometry.The two major reaction products have been identified as two isomers of LiCO2.In each case, vibrational data are consistent with a bent structure of the CO2 groups, indicating that, by analogy with the structure of CO2- anion in the gas phase, these complexes are stabilized by a strong transfer of the lithium valence electron to the CO2 group.Addition of another CO2 molecule produces two other intermediate steps to further reduction of carbon dioxide, achieved in the final high-stoichiometry product identified as lithium oxalate, Li2C2O4.
- Manceron, L.,Loutellier, A.,Perchard, J. P.
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- On the thermal behavior of Li bis(oxalato)borate LiBOB
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The lithium salt, bis(oxalato)borate, LiBC4O8 (LiBOB), is one of the most important Li salts which are explored today in connection with R & D of novel, high energy density rechargeable Li batteries. The thermal stability of this salt in the temperature range of 40-350 °C was rigorously studied by accelerating rate calorimetry (ARC), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). XRD, FTIR, SEM, and ICP were used to analyze the products of its thermal decomposition reactions. Studies by DSC and pressure measurements during ARC experiments with LiBOB detected an endothermic reaction with an onset at ～293 °C, involving a complete irreversible decomposition of the LiBOB in which gaseous products are formed. In the first stage, Li2C2O4 (crystalline), B2O3 (glass), CO and CO2 gases are formed in both confined and open volumes. The next (final) stage in the thermal reactions is an irreversible formation of lithium triborate LiB3O5 (glass).
- Zinigrad, Ella,Larush-Asraf, Liraz,Salitra, Gregory,Sprecher, Milon,Aurbach, Doron
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- A nanorod-like Ni-rich layered cathode with enhanced Li+diffusion pathways for high-performance lithium-ion batteries
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Ni-rich LiNixCoyMn1?x?yO2(x≥ 0.6) layered oxide cathodes are among the most promising cathode materials for lithium-ion batteries (LIBs) owing to their superior capacity, prominent energy density and low cost. However, the large volume change caused by phase transition and poor diffusion kinetics limits their application. Herein, a nanorod-like Ni-rich layered LiNi0.6Co0.2Mn0.2O2cathode is synthesizedviaa facile surfactant-free co-precipitation route. Due to the unique nanorod morphology, more {010} electrochemically active planes are exposed. As a result, structural stability and diffusion kinetics are greatly improved. In terms of performance, it exhibits outstanding structural stability (the volume change is as small as 2.12% in the processes of charging and discharging) and rate performance (achieving a high discharge capacity of 152.2 mA h g?1at 5C). Such rationally designed cathode could meet the high high-energy requirements of next generation LIBs.
- Li, Fangkun,Liu, Zhengbo,Shen, Jiadong,Xu, Xijun,Zeng, Liyan,Zhang, Binghao,Zhu, He,Liu, Qi,Liu, Jun,Zhu, Min
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- A method for preparing lithium of high-purity oxalic acid (by machine translation)
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The invention belongs to the electrolyte for lithium ion battery process for the preparation of the lithium salt to the technical field, discloses a method for preparing lithium of high-purity oxalic acid, the steps are as follows: 1) is prepared to oxalic acid solution, to form the 10% [...] 20% to in technical grade lithium hydroxide solution, filter mixed to the solution is clear; 2) heating step 1) residual oxalic acid solution of the 20 [...] 30% into a reaction kettle, then adding step 1) filtering good lioh solution, a small amount of white precipitate to the bottom of the generating, after sufficient reaction, the remaining filter good lioh solution and oxalic acid solution in the reaction kettle added at the same time, continued stirring, the temperature of the 50 [...] 80 °C, adjusting the pH value of 7.0 the [...] 7.5, continuing to stir the 10 [...] 30 min; 3) control step 2) the resulting lithium oxalate temperature of the solution in the 5 [...] 15 °C/h speed to normal temperature, and the bottom of the sink to all lithium oxalate; 4) drying. The technological process is simple, the implementation is strong, safe environmental protection, the purity of the product is high. (by machine translation)
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Paragraph 0027; 0028; 0029; 0030; 0031; 0032
(2017/01/02)
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- Preparation of LiBOB via rheological phase method and its application to mitigate voltage fade of Li1.16[Mn0.75Ni0.25]0.84O2 cathode
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Lithium bis(oxalato)borate (LiBOB) was synthesized via a novel rheological phase reaction method without any recrystallization procedure. The purity of the as-obtained LiBOB has been identified in comparison with the commercial sample and our sample prepared from solid-state reaction method. The results of XRD, ICP, and 11B NMR demonstrate that high pure LiBOB has been synthesized via rheological phase reaction method with significantly simplified synthetic process. Moreover, LiBOB sample has been investigated as electrolyte additive to improve the electrochemical performances of high-energy lithium-rich layered oxide. The cycling performances imply that 0.03 M and 0.05 M LiBOB additive can mitigate discharge voltage fade and enhance the cycle stability of Li1.16[Mn0.75Ni0.25]0.84O2 material. The CV, EIS and XPS data indicate that LiBOB oxidizes at ～4.3 V (vs. Li/Li+) on the cathode surface during the first charge to form a specific SEI layer with larger amount of organic species and fairly less content of LiF, which decreases the interfacial polarization and protects the active material from surface degradation, thereby mitigates the voltage-fade of Li-rich cathode.
- Lian, Fang,Li, Yang,He, Yi,Guan, Hongyan,Yan, Kun,Qiu, Weihua,Chou, Kuo-Chih,Axmann, Peter,Wohlfahrt-Mehrens, Margret
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p. 86763 - 86770
(2015/11/03)
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- N-Boc ethyl oxamate: A new nitrogen nucleophile for use in Mitsunobu reactions
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N-Boc ethyl oxamate can be directly coupled with primary and secondary alcohols under Mitsunobu conditions to afford various N-Boc mines after mild deprotection.
- Berree, Fabienne,Michelot, Gwendal,Le Corre, Maurice
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p. 8275 - 8276
(2007/10/03)
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- Remarkable Decrease in Overpotential of Oxalate Formation in Electrochemical CO2 Reduction by a Metal-Sulfide Cluster
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Triangular metal-sulfide cluster, 3(μ3-S)2>2+ and 3(μ3-S)2>2+, catalyse the electrochemical CO2 reduction to selectively produce oxalate at -1.30 and -0.70 V (vs.Ag/AgCl), respectively, in MeCN.
- Kushi, Yoshinori,Nagao, Hirotaka,Nishioka, Takanori,Isobe, Kiyoshi,Tanaka, Koji
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p. 1223 - 1224
(2007/10/02)
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- Oxalate Formation in Electrochemical CO2 Reduction Catalyzed by Rhodium-Sulfur Cluster
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Electrochemical reduction of CO2 catalyzed by a triangular rhodium complex *)3(μ3-S)2>2+ selectively produced formate and oxalate in the presence of Bu4NBF4 and LiBF4, respectively, under the controlled potential electrolysis at -1.50 V (vs.SCE) in CO2-saturated CH3CN.A solution IR spectrum evidenced the adduct formation between *)3(μ3-S)2>0 and CO2 as the possible precursor for the oxalate formation.
- Kushi, Yoshinori,Nagao, Hirotaka,Nishioka, Takanori,Isobe, Kiyoshi,Tanaka, Koji
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p. 2175 - 2178
(2007/10/02)
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- CARBON DIOXIDE ACTIVATION BY LITHIUM METAL: PART 1. INFRARED SPECTRA OF Li + CO2 - , Li + C2O4 - AND Li22 + CO22 - IN INERT-GAS MATRICES.
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Lithium atoms react spontaneously with carbon dioxide to form Li** plus CO//2** minus and Li//2**2** plus CO//2**2** minus in inert gas matrices. Reaction of Li and CO//2 in an argon matrix leads also to the formation of Li** plus C//2O//4** minus . Two geometrical isomers of Li** plus CO//2** minus have been isolated in solid argon. One has a ring structure in which the metal interacts symmetrically with the two oxygen atoms, while in the second isomer the lithium atom is bonded to only one of the two oxygens.
- Kafafi,Hauge,Billups,Margrave
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p. 3886 - 3893
(2007/10/02)
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