一步法回收和再生废旧钴酸锂电池中的钴酸锂

采用酸浸法和溶胶-凝胶法耦合的一步法技术路线回收和再生LiCoO₂,简化了流程。先使用柠檬酸浸出正极材料中的Co和Li元素,然后采用溶胶-凝胶法从浸出液中直接再生LiCoO₂,柠檬酸在过程中起到了浸出剂和螯合剂的双重作用,简化了回收和再生流程。摸索了柠檬酸浓度、固液比、浸出温度、H₂O₂体积浓度和浸出时间对Co和Li浸出效率的影响规律,探究了煅烧温度对再生钴酸锂结构组成、颗粒形貌以及电化学性能的影响规律。结果表明,最佳浸出条件为：柠檬酸浓度为1.5mol/L,固液比为20g/L,浸出温度为80℃,H₂O₂体积分数为2%,浸出时间为60min。在此条件下,Co和Li的浸出率分别达到93.7%、98.2%。通过电化学分析表明,在700℃下煅烧得到的再生LiCoO₂电化学性能最佳,在1C下经50次循环后可逆放电比容量为118.7mA·h/g,容量保持率为93%。     

Combined X-ray study of lithium (tin) cobalt oxide matrix negative electrodes for Li-ion batteries

The lithium insertion behaviours of the oxides Co₃O₄ and Co₂SnO₄ were studied using a range of electrochemical, spectroscopic and diffraction techniques. Co K-edge EXAFS studies on the Co₃O₄ oxide showed that the reversible lithium insertion is coupled with changes in cobalt oxidation state. On lithium insertion, Co₃O₄ is reduced to yield Co(II) and yields only metallic cobalt species on complete reduction. On lithium removal an oxide of Co is formed, which from coulometry should be CoO, however, EXAFS indicates the short range structure is quite different to that of the rocksalt CoO. The long range structure of the matrix is amorphous according to XRD. The EXAFS and XRD data also revealed that both the metallic and oxide phases were disordered, having low co-ordination numbers and large shell spacings, and that there was an initial reduction to CoO before full reduction to metallic Co. The electrochemical behaviour of Co₂SnO₄ cells was more reminiscent of that of SnO₂ than that of Co₃O₄, but did exhibit significant differences due to the presence of cobalt. EXAFS on Co₂SnO₄ cells revealed that Co is reduced to metallic cobalt on the initial discharge, but that it does not convert back to an oxide on cycling even though the electrochemical treatment was the same as for Co₃O₄. Together the EXAFS and Mössbauer data show that the Co and Sn are reduced concurrently, and that some of the Sn remains in the oxidised form. In summary, we have a surprising result in that the presence of the tin dramatically changes the redox behaviour of the cobalt. In a matrix derived from a cobalt oxide spinel, cobalt undergoes redox cycling, whereas in a matrix derived from a cobalt tin oxide spinel, the cobalt does not cycle whilst the tin does.     

A kinetic study of the electroreduction of anodically formed cobalt oxide layers

The kinetics of the electroreduction of anodically formed cobalt oxide layers in different carbonate-bicarbonate aqueous solutions were investigated using combined voltammetric and potential step techniques. The composition of the electrolyte was varied to cover wide pH and ionic strength ranges. The electroreduction reaction can be explained through a nucleation and three-dimensional growth process, involving cobalt phase formation from either soluble Co(II) or Co(III) species.     

饲料级氯化钴的研制

以36%工业盐酸和工业氧化钴为原料制取氯化钴,研究了配料比等反应条件对产物产率的影响。结果表明,适宜的制取条件为:n(盐酸)∶n(氧化钴)为1.96∶1,反应温度49℃,反应时间65 m in,搅拌速度130~140 r/m in。在此条件下,产率为90.86%,含量为98.12%,相对较高。     

Silica-supported cobalt catalysts for the selective reduction of nitrogen monoxide with propene

Catalytic behavior of silica-supported transition metals for NO reduction with propene in the presence of oxygen was investigated. While both silica and cobalt oxides did not show any activity for the selective NO reduction, impregnated CoO/SiO₂ prepared from cobalt acetate showed good activity although the preparation conditions had significant effect on the activity. It was suggested that highly dispersed surface Co²⁺ ions on silica are responsible for the catalytic activity.     

Influence of different lithium sources on the morphology,structure and electrochemical performances of lithium-rich layered oxides

Lithium-rich layered oxides were synthesized via co-precipitation by using different lithium sources (LiOH, Li₂CO₃ and CH₃COOLi). Scanning electron microscope (SEM), Thermo gravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), Inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD) and electrochemical measurements were used to investigate the morphology, reaction process, specific surface area, composition, structure and electrochemical performance of the lithium-rich oxides, respectively. The use of different lithium sources mainly affects the primary particle size and secondary particle morphology of the final product. Using LiOH as the lithium source, the maximum discharge capacity of sample can reach to 272.1 mA h g^–1 in the voltage range of 2.0–4.6 V at room temperature, even after 50 cycles, the retention rate is still reach 91.4%. The electrochemical impedance spectroscopy (EIS) results show that lithium-rich oxides using LiOH as the lithium source have the minimum value of impedance after 50 cycles. Therefore, the choice of appropriate lithium source is an effective way to improve the electrochemical properties of lithium-rich layered oxides.     

Ionic conductivities for poly(ethylene oxide) complexes with lithium salts of monobasic and dibasic acids and blends of poly(ethylene oxide) with lithium salts of anionic polymers

Lithium salts of two polyanionic addition polymers containing alkyl sulphonic acid and perfluoroalkyl carboxylic acid side groups were prepared. Blends of these polymers were formed with poly(ethylene oxide) (PEO). The blend containing alkyl sulphonate units showed some phase separation but this was not observed for the blend containing perfluoroalkyl carboxylate groups. In the latter case a comparatively high conductivity of $\text{～10}{}^{\mathrm{?5}}\text{Ω}{}^{\mathrm{?1}}$ cm^?1 at 374 K was obtained. The anionic units in these blends are expected to be virtually immobile. Complexes formed from PEO and the Li-salt of hexafluoroglutaric acid had similar high ionic conductivities and there are grounds for supposing that the anions in these complexes may also be substantially immobilized. In addition, conductivity values were obtained for some PEO complexes containing lithium salts of some monobasic acids and it was found that the complex formed from the Li-salt of the strongest acid gave the highest conductivity ($\text{～4 × 10}{}^{\mathrm{?4}}\text{Ω}{}^{\mathrm{?1}}$ cm^?1 at 373 K for a PEO-LiSO₃CF₃ complex).     

Coating metal oxide particles via the combustion of deposited polymer precursors

Water-swellable chelated polymers were synthesized, starting either from (1) In(III) or In(III) and Sn(II) as central ions and N-trimethoxysilylpropylethylenediamine or ethylenediamine each together with ethylenediaminetetraacetic acid (EDTA) as coordination ligands, or from (2) Ag(I) as the central ion and ethylene glycol (EG) and EDTA as coordination ligands, as follows: The nitrate(s) of the above metal ions together with the corresponding ligands were dissolved in water, and the solution was concentrated by heating to carry out the chelating polymerization. After cooling, the polymer was dried and ground to a fine powder, which was then mixed with a metal oxide powder by grinding in the presence of a small amount of water. A paste was thus obtained, which, after drying, was calcined at 200°C and subsequently at 750°C. The polymer became a sticky gel at 200°C, which adhered to the surface of the metal oxide particles; it was converted to an inorganic coating, In₂O₃—SnO₂—SiO₂, In₂O₃—SnO₂, SnO₂, or Ag, during the subsequent calcination at 750°C. Two metal oxide powders, namely, the electrically conductive In₂O₃ and the nonconductive SnO₂, were used as substrates. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) indicated that the substrate particles were coated after calcination by a multicomponent oxide or silver layer. Temperature-resistant electrically antistatic film could be prepared by using the metal oxide coated In₂O₃ particles as pigments and polypropylsiloxane as the binder. The Ag-coated SnO₂ powder had a conductivity σ = 1.0 × 10⁻³ S cm⁻¹ at 8.6 vol % Ag, while the mechanically mixed powders of Ag and SnO₂ exhibited a conductivity of 2.0 × 10⁻⁷ S cm⁻¹ at 16 vol %. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1891–1903, 1998     

Morphology and ionic conductivity of some lithium ion complexes with poly(ethylene oxide)

Deposition of LiBF₄-PEO crystalline complexes from methanol gives a material (phase II) melting at ～340K while deposition from acetone-chloroform mixtures gives a material with a melting point of ～433K (phase I). Both materials have the same 1:4 stoichiometry (Li⁺:ethylene oxide) and each gives the same wide-angle X-ray scattering pattern though phase II has the broader reflections. The observations are interpreted in terms of a double helical model with long sequences of the same helical sense for phase I, but with less long range order and frequent reversals of helical sense for phase II. The presence of both phases in LiCF₃SO₃ complexes is attributed to the contribution of the anion towards complex stability in methanol. The conductivities of the semicrystalline materials are compared with those of amorphous PEO gels complexed with LiBF₄. The highest ambient temperature conductivities are obtained from complexed gels.     

Thermoelectric properties and stability of the Re0.2Sr0.8CoO3-δ Re = Gd,Dy) complex cobalt oxides in the temperature range of 300‒800 K

Temperature dependences of the electrical resistivity and Seebeck coefficient of the Re_0.2Sr_0.8CoO_3?δ Re =?Gd, Dy) complex cobalt oxides in the temperature range of 300 – 800?K have been investigated. The effects of ordering in the cation and anion sublattices on the thermoelectric properties has been examined and their comparative analysis has been made. It was found that, in the investigated temperature range, the thermoelectric power factor of the ordered compounds significantly exceeds the analogous parameter of the disordered samples. The temperature dependence of the electrical resistivity was shown to obey the activation law. As the temperature increases, the samples undergo a semiconductor-semiconductor electronic transition with a decrease in the activation energy. The thermoelectric properties of all the samples are shown to be stable in the investigated temperature range. The maximum thermoelectric power factor of the ordered Dy_0.2Sr_0.8CoO_2.67 cobaltite at a temperature of 360?K has been obtained; it amounts to 0.23?µW/(cm·K²), which is a good parameter for this class of materials.     

Safety evaluation of rechargeable cells with lithium metal anodes and amorphous V2O5 cathodes

Rechargeable cells with lithium metal anodes have a very large theoretical energy density and are a promising cell system. However, rechargeable lithium metal cells are not yet currently commercially available. One of the biggest problems with the cells is the poor safety aspect resulting from the high chemical reactivity of lithium. We have been studying a cell system consisting of an amorphous (a-)V2O5P2O5 (95:5 in molar ratio) cathode, a lithium (Li) metal anode and an organic electrolyte in fabricating an AA-size prototype. In this paper, we report recent progress on our rechargeable lithium metal cell focusing on its safety.     

化学交换法分离锂同位素的理论及新技术研究进展

发展核能是我国可持续发展的重要举措,锂作为重要的能源战略金属,锂同位素（⁶Li、⁷Li）分离是核能开发必须解决的关键技术难题,受到国际及国内科学家的广泛关注。⁶Li、⁷Li具有完全相同的电子结构,两者具有几乎相同的化学性质,分离难度极大。本文简要回顾了20世纪60年代以来化学交换法分离锂同位素取得的进展,重点综述了同位素分离的理论研究以及近五年来锂同位素分离的新材料、新介质。针对目前冠醚在分离锂同位素过程中存在的冠醚分子易流失、Li⁺的分配系数低等问题对现有的研究和报道进行了总结,有望为锂同位素分离新材料和新体系的开发提供指导。     

Synthesis of linear low density polyethylene (LLDPE) by in situ copolymerization with novel cobalt and zirconium catalysts

New cobalt catalysts {[2,6‐(CH₃C=NAr)₂C₅H₃N]CoCl₂} (Ar=2‐methyl‐4‐methoxyphenyl, 1 ) and (Ar=2,4‐dimethylphenyl,2) were synthesized and found to exhibit good selectivity for α‐olefins with methylaluminoxane (MAO) as co‐catalyst. With only ethylene as the feed monomer cobalt catalysts 1 or 2 can be coupled with zirconium catalyst Dichloro [rac‐ethylenebis(indenyl)]Zirconium (IV) rac‐EtInd₂ZrCl₂ ( 3 ) to produce linear low density polyethylene by in situ polymerization. Spectra of resulting materials exhibit ethyl, butyl and long‐chain branches in the backbone of polyethylene. The ratio of Co/Zr and Δt, which is defined as the interval between introductions of two catalysts into the reactor, influenced catalytic activity and the resulting materials greatly. Compatibility and complementary behaviour of different catalysts proved to be two most important factors for in situ copolymerization. Copyright © 2003 Society of Chemical Industry     

Enhanced ion conductivity of poly(ethylene oxide)-based single ion conductors with lithium 1,2,3-triazolate end groups

Poly(ethylene oxide) (PEO)-based single ion conductors (SICs) are of great interest for applications in modern lithium ion batteries. They have several advantages over other common electrolytes such as high cation transference numbers, low toxicity, and nonflammability, but their major disadvantage is the low ion conductivity. Here, linear PEO-based SICs with lithium 1,2,3-triazolate (TrLi) end groups are synthesized and studied in terms of crystallinity by differential scanning calorimetry, and with respect to ion conductivity by impedance spectroscopy. Introduction of TrLi end groups to PEO chains reduces its crystallinity and melting temperature as well as an enhancement of the ion conductivity up to 8.0·10⁻⁶ S cm⁻¹ at 70°C is observed. The increased ion conductivity is a direct result of the Tr rings, which can actively contribute to the conduction mechanism. In comparison with conductivities of other PEO-based SICs reached so far (σ₀ ≤ 10⁻⁶ S cm⁻¹), the results of this study show that the introduction of TrLi end groups is a new approach to enhance the Li⁺-ion conductivity of PEO-based SICs that have also a good electrochemical stability versus lithium electrodes as revealed by linear sweep voltammetry. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46949.     

Adhesion of vacuum-deposited thin cobalt metal film to poly(ethylene terephthalate) pretreated with RF plasma

Specific polar groups were introduced on a poly(ethylene terephthalate) (PET) film surface by radio-frequency (RF) plasma treatment. These polar groups were analyzed quantitatively by ESCA, and their effect on the adhesion strength of vacuum-deposited thin cobalt metal film on the plasma-treated PET film surface was investigated. Hydroperoxide and hydroxyl groups introduced onto the PET film surface by RF plasma under an argon or oxygen atmosphere greatly increased the adhesion strength. In particular, oxygen plasma treatment at high RF power was most effective. A large number of amino groups were introduced by the ammonia plasma treatment, but they did not increase the adhesion strength.     

具有不同组成的镍钴锰三元材料的最新研究进展

镍钴锰三元材料近年来在移动电话、笔记本、数码相机等电子设备电池的应用方面取得了巨大的成功,相关研究及开发也得到了学术界的空前关注。镍钴锰三元材料为三元材料中最为重要的一类材料,目前已有多种这类三元材料成功地应用于锂离子电池。本文将介绍近年来镍钴锰三元材料的一些最新研究进展,主要介绍几种典型的具有不同镍钴锰比例的几类三元材料(333,523,811,622,424)的制备技术、结构研究、性能研究、掺杂及包覆改性等方面的研究进展,并对这些材料的应用前景及存在的问题做了简介。并在此基础上,对镍钴锰三元材料的未来发展趋势作了展望。     

Electrochemical performance of all-solid-state lithium secondary batteries with Li-Ni-Co-Mn oxide positive electrodes

LiNi_1/3Co_1/3Mn_1/3O₂ was applied as a promising material to the all-solid-state lithium cells using the 80Li₂S·19P₂S₅·1P₂O₅ (mol%) solid electrolyte. The cell showed the first discharge capacity of 115 mAh g⁻¹ at the current density of 0.064 mA cm⁻² and retained the reversible capacity of 110 mAh g⁻¹ after 10 cycles. The interfacial resistance was observed in the impedance spectrum of the all-solid-state cell charged to 4.4 V (vs. Li) and the transition metal elements were detected on the solid electrolyte in the vicinity of LiNi_1/3Co_1/3Mn_1/3O₂ by the TEM observations with EDX analyses. The electrochemical performance was improved by the coating of LiNi_1/3Co_1/3Mn_1/3O₂ particles with Li₄Ti₅O₁₂ film. The interfacial resistance was decreased and the discharge capacity was increased from 63 to 83 mAh g⁻¹ at 1.3 mA cm⁻² by the coating. The electrochemical performance of LiNi_1/3Co_1/3Mn_1/3O₂ was compared with that of LiCoO₂, LiMn₂O₄ and LiNiO₂ in the all-solid-state cells. The rate capability of LiNi_1/3Co_1/3Mn_1/3O₂ was lower than that of LiCoO₂. However, the reversible capacity of LiNi_1/3Co_1/3Mn_1/3O₂ at 0.064 mA cm⁻² was larger than that of LiCoO₂, LiMn₂O₄ and LiNiO₂.     

Enhancement of the denitrification efficiency over low-rank activated coke by doping with transition metal oxides

Low-rank activated coke (AC) is widely used for industrial flue gas purification due to its multipollutant cooperative removal capability. To enhance the denitrification capacity of AC for the selective catalytic reduction (SCR) of NO with NH₃, several transition metal (Fe, Mn, Ce, V) oxides were uniformly loaded into AC by solvent impregnation. Compared to untreated AC, modified AC showed excellent denitrification efficiency above 90%. N₂ adsorption-desorption and Raman spectroscopy techniques were used to characterize the pore size distribution and crystal structure of AC samples. The introduction of transition metal oxides had little effect on the pore structure of AC but increased the nitrogen-containing functional groups, which facilitated NO removal. Moreover, x-ray photoelectron spectroscopy (XPS) was used to analyze the valence changes of metal elements before and after denitrification. After the reaction, the content increase of the low-valence metal oxides indicated that the transition metal oxides were involved in the reaction of NO with NH₃. High-valence metal oxides oxidized NO to NO₂, which reacts more easily with NH₃, thereby increasing the denitrification efficiency. Importantly, in the presence of SO₂, modified AC still presented high denitrification performance. This transition metal oxides doping method can effectively improve the ability of low-rank AC to remove NO in multi-contaminant flue gas.     

Causticization of sodium carbonate with rock-salt type magnesium aluminium oxide formed by the thermal decomposition of hydrotalcite-like layered double hydroxide

The causticization behaviour of Na₂CO₃ with rock-salt type oxide, Mg_2(1-x/(2+x) O (M = Al³⁺ and Fe³⁺, x = 0.2 and 0.33), produced by the thermal decomposition of hydrotalcite-like layered double hydroxide was investigated at 30–60°C. The degree of causticization increased with increasing the molar ratio of [rock-salt type oxide]/[Na₂CO₃] and increasing the temperature but decreased with increasing the initial concentration of Na₂CO₃. The causticization behaviour could be adequately described by the equation of anion exchange equilibria between CO₃^2- and OH^? for layered double hydroxide.     

钛基金属氧化物涂层电极的研究进展

钛基金属氧化物涂层电极又称DSA,是一种新型不溶性阳极电极。综述了钛基金属氧化物涂层电极的研究进展,包括钛基钌系涂层电极、钛基铱系涂层电极、钛基二氧化锰电极和钛基二氧化铅电极。介绍了不同钛基涂层电极材料的制备方法、性能特点和应用情况,并对其今后的发展方向作了展望。