安太堡11号煤层中锂镓分布赋存的差异性研究

为针对性分析煤层中锂、镓的分布赋存特征,选取安太堡11号煤层为研究对象,统计了锂、镓在各灰分级别、硫分级别及纵向分层中的分布特征。通过飞行时间二次离子质谱仪与带能谱的扫描电镜,分析了微区范围内锂、镓与常量元素的结合关系,讨论了煤层中锂、镓赋存状态差异性及影响因素。结果表明,锂富集于高灰煤中,镓在不同灰分级别与硫分级别煤中含量变化不显著。在纵向煤层中,锂在陆源物质供给充分时具有较高含量,镓分布较为均匀未呈现明显变化规律。微区原位分析中,锂的赋存与铝硅酸盐密切相关,镓可赋存于高岭石、勃姆石、黄铁矿、钠盐和钾盐中。煤层中锂与稳定元素锆的相关性系数为0.894,两者主要来源于物源区酸性岩浆岩。镓由于过渡元素的性质显示亲石性与亲硫性,在高灰煤与高硫煤中均具有较高含量,较强的元素迁移性使其在煤分层中趋于均匀分布。     

锂的石墨炉原子发射分析方法的研究

痕量锂在人体内已成为不可缺少的元素,对疾病的控制或临床上的诊断以及对环境、医学及生物的研究都有明显的意义。由于一般分析方法灵敏度不高,对锂的检测比较困难。Ottaway等采用石墨炉原子发射法以标准石墨管测定锂和其它某些元素,检出限比火焰发射法和石墨炉原子吸收法有明显的改善,并应用于纯铜中痕量锂的测定。Matousek等研究了锂的石墨炉原子发射方法,在入口狭缝处使用档光技术降低背景发射,提高了     

取代环戊二烯负离子的三甲基硅基化

以６,６－二烷基富烯与甲基锂、苯基锂或对甲苯基锂所犁 取代环戊二烯基锂与三甲基氯硅烷反应,合成了１１个新的三甲基硅基环戊二烯化合物,其结构经元素分析、ＩＲ和＾１ＨＮＭＲ确证。     

锂元素的分析方法探讨

总结了国内外关于测定锂元素的分析方法,内容主要包括质量分析法、光谱分析法和波谱分析法,并侧重分析了各种方法的优缺点,指出了提高锂分析结果精度的可能途径。     

电感耦合等离子体发射光谱法测定岩矿中锂的含量

采用氢氟酸加高氯酸分解试样,硝酸浸取,电感耦合等离子体原子发射光谱法测定岩矿中的锂含量。测定范围: ω(Li)：0.10%～10.00%。本文通过不同混合酸溶样效果比较,仪器条件的摸索、共存元素干扰实验等,建立了电感耦合等离子体原子发射光谱法测定岩矿中锂量的方法,完全能够满足岩矿中锂含量的检验工作。经加标回收实验,锂元素的加标回收率为98%~106%(n=3),经国家有证标准物质分析验证,测定结果与标准值一致。该方法准确简单,适用于岩矿中的锂测定。     

X射线荧光光谱法测定钒铁合金中主次元素含量

用熔融制样法将钒铁合金样品在铂金坩埚中与四硼酸锂和偏硼酸锂熔融,熔体在铂金坩埚中自动成型,用X射线荧光光谱法测定钒铁合金中钒、硅、锰、铝和磷等主次元素含量。经试验求得熔融时,四硼酸锂、混合溶剂(四硼酸锂∶偏硼酸锂=67∶33)和样品的最佳质量比为30比5比1。各元素的检出限在12.4～51.2μg.g-1之间。方法用于标准样品分析,测定值与认定值相符。     

火焰原子吸收光谱法测定金属锂中钠

锂作为21世纪的能源金属,在近年得到迅猛发展。它以其特有的核性质成为一种极具发展潜力的稀有元素,由于锂无裂变产物,不会造成辐射污染,已成为发展尖端技术的重要材料。但由于锂中钠、硅、钙等杂质元素的存在,影响了锂的物理化学性质。所以测定金属锂中钠的含量对保证产品的质量至关重要。锂的化合物中微量元素的测定多采用原     

锂标准电极电势反常现象的热力学讨论

在IA族中,锂的标准电极电势是最负的,但锂的还原性却是同族元素中最弱的,这与利用标准电极电势来判断碱金属的还原性是相互矛盾的.本文利用玻恩-哈伯循环,从热力学角度探讨了锂标准电极电势出现反常现象的原因.     

掺铝富锂材料Li1.2Mn0.543Co0.078Ni0.155Al0.030O2电极的电化学性能

本文合成了掺铝富锂材料Li_1.2Mn_0.543Co_0.078Ni_0.155Al_0.030O₂,并使用扫描电镜（SEM）、粉末X射线衍射（XRD）、电感耦合等离子体原子发射光谱（ICP-AES）和拉曼散射光谱（Raman）等观察表征富锂和掺铝富锂材料. 结果表明,共沉淀法合成掺铝富锂材料,具有R-3m空间群结构,Al元素进入晶格,未单独成相. 电化学性能和非现场XRD测试结果表明,4%（by mole）掺铝富锂电极100周期循环容量保持率83.7%,Al元素掺杂有利于容量的释放,增强了电极富锂材料的结构稳定性,提高了循环性能.     

青藏高原湖泊影响锂元素迁移和富集的矿物、元素及环境因素——以西藏郭扎错钻孔沉积物为例

作为我国战略性矿产的锂矿,主要赋存于青藏高原盐湖中。湖泊系统中,锂的富集和迁移规律关系到锂矿的高效提取和未来锂矿的储量估算。本文以西藏咸水湖郭扎错的钻孔沉积物为例,结合AMS14C年代和Mg元素含量变化,系统分析了孔隙水、碳酸盐矿物和硅酸盐矿物的锂含量变化,探讨了矿物、镁元素、环境变化和早期成岩作用等对锂元素迁移和富集的影响。郭扎错沉积物中锂和镁大部分存在于硅酸盐矿物中,锂和镁较高的相关性说明二者存在于相同的硅酸盐矿物中,如粘土矿物。大约90%的锂赋存在硅酸盐矿物中,约8.5%的锂赋存在碳酸盐矿物中,孔隙水中的锂含量占比仅约1.5%。碳酸盐矿物中Mg/Li摩尔比值为78–270,是孔隙水中10多倍,而硅酸盐矿物中的Mg/Li摩尔比值稳定在24–29之间。水–沉积物相互作用促进硅酸盐矿物中锂的释放,咸水环境下释放的锂多于淡水环境下。碳酸盐矿物中,锂和镁主要存在于方解石中。镁离子对锂离子的迁移具有阻碍作用,低温、高盐度下的阻碍作用更强。湖泊沉积物可能是湖水锂的一个重要来源。     

单离子导体聚合硼酸锂盐的研究进展

目前商业化锂离子电池常用的锂盐LiPF6,对水极其敏感,热稳定性差,尤其是在高温条件下的应用存在着一定的安全隐患.种类多且环境友好的新型有机硼酸锂盐越来越受到人们的重视.本文综述了近年来几种锂盐的合成方法,电化学性能,各自存在的优点和不足以及本课题组在聚合硼酸锂盐方向取得的系列研究进展,并对锂盐和聚合物电解质的发展方向进行了展望.     

基于表界面反应及优化的锂金属电池研究进展

金属锂具有高理论比容量和低还原电位, 是锂电池阳极的理想材料之一. 但在长期循环充放电过程中, 金属锂因锂枝晶生长会导致出现界面恶化及能量损失严重等问题, 对锂金属电极与电解质表界面反应的优化是一个重要研究方向. 本文介绍了锂枝晶产生的危害, 从分析及抑制锂枝晶沉积两方面综合评述了为解决这一问题所采取的方法, 包括固态电解质界面形成机制和保护机理、 表面改性、 三维锂阳极和液态/固态电解质等方法, 总结了各种方法的优劣势, 并展望锂金属电池在能源领域的研究前景.     

Mechanism of meerwein-pondorf-verley type reductions

The reduction of benzophenone by lithium and chloromagnesium alkoxides has been studied as well as the transformation of certain lithium alkoxides to the corresponding ketones by electron transfer. Fluorenone was reduced by lithium sec-butoxide to the corresponding lithium ketyl to the extent of 65%. Lithium 9-fluoroenolate underwent in tetrahydrofuran a spontaneous transformation to lithium fluorenone ketyl. This process was interpreted as involving 1,2-hydrogen shift in an oxygen-centred radical. A mechanism for the Meerwein-Pondorf-Verley-type reductions is proposed, invoking single electron as well as 1,2-hydrogen shift steps.     

Mechanisms of lithium transport in amorphous polyethylene oxide

We report calculations using a previously reported model of lithium perchlorate in polyethylene oxide in order to understand the mechanism of lithium transport in these systems. Using an algorithm suggested by Voter, we find results for the diffusion rate which are quite close to experimental values. By analysis of the individual events in which large lithium motions occur during short times, we find that no single type of rearrangement of the lithium environment characterizes these events. We estimate the free energies of the lithium ion as a function of position during these events by calculation of potentials of mean force and thus derive an approximate map of the free energy as a function of lithium position during these events. The results are consistent with a Marcus-like picture in which the system slowly climbs a free energy barrier dominated by rearrangement of the polymer around the lithium ions, after which the lithium moves very quickly to a new position. Reducing the torsion forces in the model causes the diffusion rates to increase.     

A Chemically Bonded Ultraconformal Layer between the Elastic Solid Electrolyte and Lithium Anode for High-performance Lithium Metal Batteries

Although high ionic conductivities have been achieved in most solid-state electrolytes used in lithium metal batteries (LMBs), rapid and stable lithium-ion transport between solid-state electrolytes and lithium anodes remains a great challenge due to the high interfacial impedances and infinite volume changes of metallic lithium. In this work, a chemical vapor-phase fluorination approach is developed to establish a lithiophilic surface on rubber-derived electrolytes, which results in the formation of a resilient, ultrathin, and mechanically integral LiF-rich layer after electrochemical cycling. The resulting ultraconformal layer chemically connects the electrolyte and lithium anode and maintains dynamic contact during operation, thus facilitating rapid and stable lithium-ion transport across interfaces, as well as promoting uniform lithium deposition and inhibiting side reactions between electrolyte components and metallic lithium. LMBs containing the novel electrolyte have an ultralong cycling life of 2500 h and deliver a high critical current density of 1.1 mA cm⁻² in lithium symmetric cells as well as showing good stability over 300 cycles in a full cell.     

Lithium isotope effects in extraction of lithium chloride by benzo-15-crown-5 in the 1,1,7-trihydrododecafluoroheptanol–water system

The extraction characteristics of the 1,1,7-trihydrododecafluoroheptanol water system have been studied for lithium chloride as the salt to be extracted and benzo-15-crown-5 as the extracting agent, as well as blank extraction of lithium chloride in this system. Single-stage lithium isotope separation factors (a) have been measured at various lithium chloride concentrations in water, and the isotope effect has been multiplied by extraction chromatography. The value of a for the Li⁶–Li⁷ pair was 1.024. The light lithium isotope is concentrated in the organic phase.     

REDOX POTENTIALS AND DIFFUSION OF LITHIUM IN LAMELLAR COMPOUNDS

Abstract

Themodynamic and dynamic properties of intercalation products of lithium into MoS₂ are strongly determined by the coordination of lithium in the interlaminar spaces. Lithium redox potentials as well as lithium diffusion coefficients in MoS₂ pure, exfoliated, as well as in compounds where lithium is co-intercalated with the polymeric electron pair donors, poly(ethylene oxide) and poly-acrylonitrile, and discrete species, OH^? ions and secondary amines, were analyzed comparatively. Reduction potentials in pure or exfoliated MoS₂ are always much lower than those observed in lithium-donor co-intercalates. Thus, donors appear to effectively stabilize higher lithium oxidation states. The donors also influence lithium migration properties, with lithium diffusion coefficients in general higher than in pure MoS₂. Lithium diffusion activation energy in pure MoS₂ is constant in a relatively large lithium concentration range, while for co-intercalates it often depends on lithium intercalation degree. These more complex diffusion mechanisms probably arise from changes in the donor conformation in the interlaminar spaces, which affect the lithium first coordination sphere.     

Bio‐Inspired Stable Lithium‐Metal Anodes by Co‐depositing Lithium with a 2D Vermiculite Shuttle

Progress in lithium‐metal batteries is severely hindered by lithium dendrite growth. Lithium is soft with a mechanical modulus as low as that of polymers. Herein we suppress lithium dendrites by forming soft–hard organic–inorganic lamella reminiscent of the natural sea‐shell material nacres. We use lithium as the soft segment and colloidal vermiculite sheets as the hard inorganic constituent. The vermiculite sheets are highly negatively charged so can absorb Li⁺ then be co‐deposited with lithium, flattening the lithium growth which remains dendrite‐free over hundreds of cycles. After Li⁺ ions absorbed on the vermiculite are transferred to the lithium substrate, the vermiculite sheets become negative charged again and move away from the substrate along the electric field, allowing them to absorb new Li⁺ and shuttling to and from the substrate. Long term cycling of full cells using the nacre‐mimetic lithium‐metal anodes is also demonstrated.     

Recent advances in metal-organic frameworks for lithium metal anode protection

The lithium metal battery has been considered as a promising candidate for next generation batteries.However,safety concerns caused by uncontrollable lithium dendrite growth on lithium anode are severely hampering the commercial application.Metal-organic frameworks(MOFs)become one of the most attractive materials due to the high porosity,structural designability and tunability.With unique open channels and pores as well as functional components in MOFs,the transportation and deposition of lithium ions can be regulated,which leads to enhanced electrochemical prope rties.Various strategies for lithium metal protection are proposed in recent wo rks on applications of MOFs in lithium metal batteries.In this review,we highlight latest key approaches in this field and discuss the prospects for MOFs in advanced Li anodes.     

三元锂离子电池容量衰减机理研究进展

三元锂离子电池主要是指使用镍钴锰酸锂（NCM）或镍钴铝酸锂（NCA）作为正极材料的锂离子电池,三元锂离子电池广泛应用于电动汽车、3C电子产品、储能等领域。然而,三元锂离子电池的循环寿命已成为其进一步发展的最大障碍,因此了解三元锂离子电池的容量衰退机理具有重要意义。三元锂离子电池的衰退机理主要包括五个方面：晶体结构的改变和相变、活性材料的损失、电解质的分解和消耗、可脱嵌锂离子的损耗以及固体电解质界面的形成。本文总结了近年来相关方面的研究进展,以期更全面地总结三元锂离子电池的容量衰减机理,并对三元锂离子电池的应用前景进行了展望。