锰代谢异常的临床表现

介绍了锰的生理作用、锰缺乏和锰中毒的临床表现，并对缺锰和锰中毒的防治进行了讨论。     

2—（8—羟基喹啉—5—磺酸—7—偶氮）—变色酸催化荧光法测定痕量锰（Ⅱ）

２－（８－羟基喹啉－５－磺酸－７－偶氮）－变色酸在碱性介质中分解，Ｍｎ（Ⅱ）该反应具有强烈的催化作用，基于此建立了痕量锰的测定方法；研究了测定痕量锰的最佳条件及线性范围、检测下限等。方法用于铝合金样品及污染硅片中痕量锰的测定，结果令人满意。此外详细探讨了反应机理及反应动力学方程。     

锰与社会

本文简要介绍锰的存在和发现,锰在钢铁冶金中的应用,锰盐的生产和广泛用途,以及锰与人体健康的关系。     

湖南省湘潭锰矿596名儿童发锰含量的调查报告

对湖南湘潭锰矿地区空气、水质、土壤和食物中标元素浓缩状态进行调查，同时对锰区１～１４岁儿童共５９６例发锰含量作了调查研究．以求得锰工业区儿童发锰含量的本底值．以便进一步探讨锰污染对人体健康的影响．检测结果：湘潭锰矿儿童发锰上限１５．８４×１０－６～１６．２４×１０－６，高于国内正常发锰上限的０．６５７倍，高于湖南医科大学附二院儿童发锰正常值的３．８６倍．锰区降尘比国家规定高４．８５倍，土壤比非锰区高９．７４倍，大米比非锰区高０．７５倍，井水、池塘水分别高于国家标准５８．６倍和１１．５倍，大气高于国家规定０．６倍．表明湘潭锰矿地区锰元素高度浓缩状况（污染状况）．儿重发锰测定结果与该地区环境中的锰含量成正相关．发锰可作为锰浓缩地区的指示器，为环保、公卫工作提供科学依据。鉴于该矿从事锰作业２５年者出现严重的锰中毒脑病．从而提示体内锰过多可引起脑功能障碍，与儿童智力精神的影响相关．正在进一步探讨高浓度的锰对正在生长发育中的儿童潜在影响和远期危害．     

锰试剂在有机合成中的应用

主要综述了近年来有机锰化合物及单质锰直接参与的有机反应有机合成中的应用。     

熔融浸渍法合成单晶锰酸锂作为锂离子电池阴极材料(英文)

以二氧化锰和氢氧化锂为原料,通过熔融浸渍法合成具有尖晶石构型的单晶锰酸锂。前驱体β-MnO2以乙酸锰和过硫酸钠为原料通过水热反应合成。基于TGA/DTA测试,确定了单晶锰酸锂的煅烧温度为470℃预烧5 h,再升温至750℃保温12h。XRD,FTIR和SEM结果表明,合成的单晶锰酸锂具有均一的棒状结构以及良好的结晶性。电化学性能测试结果表明材料在0.1C倍率下充放电时,其首次放电比容量可达126 mAh·g-1,且在一百次循环之后容量保持率为91%。     

高温合成锰酸锶镧的缺陷

严格按照化学式拟定配方,采用固相合成方法合成的锰酸锶镧材料中含有杂相La2O3.借助XRD,DSC,TG等分析手段分析了高温合成锰酸锶镧的缺陷,尝试对锰酸锶镧进行高温再处理,结果获得的纯锰酸锶镧不含La2O3杂相.     

全自动电位滴定法测定镍钴锰酸锂中残余的碳酸锂含量

采用自动电位滴定法测定镍钴锰酸锂中残余的碳酸锂含量。试样经搅拌水浸出其中的残余碳酸锂,用盐酸进行滴定。对试样进行11次平行测定,相对标准偏差(RSD)小于3.2%。在镍钴锰酸锂试样中加入基准物质无水碳酸钠进行碳酸根的加标回收实验,碳酸根的加标回收率在97.7%~103%。方法测定结果准确、可靠。     

熔融浸渍法合成单晶锰酸锂作为锂离子电池阴极材料

以二氧化锰和氢氧化锂为原料,通过熔融浸渍法合成具有尖晶石构型的单晶锰酸锂。前驱体β-MnO₂以乙酸锰和过硫酸钠为原料通过水热反应合成。基于TGA/DTA测试,确定了单晶锰酸锂的煅烧温度为470℃预烧5h,再升温至750℃保温12h。XRD,FTIR和SEM结果表明,合成的单晶锰酸锂具有均一的棒状结构以及良好的结晶性。电化学性能测试结果表明材料在0.1C倍率下充放电时,其首次放电比容量可达126mAh·g^-1,且在一百次循环之后容量保持率为91%。     

锰摄入标准的确立

锰是人体必需的微量元素,然而关于锰摄入标准的规定都是相互矛盾的。通过分析几种沿用的生理学指标,认为联合多项生物学指标可以更好衡量锰摄入标准。     

液相法合成锂离子电池正极材料Li_(1+x)Mn_2O_4

采用柠檬酸络合和溶液浸渍两种方法制备Li1+xMn2 O4正极材料 ,用XRD和BET测试了材料晶体结构和比表面积 ,考察焙烧温度、Li/Mn比、起始原料对产物结构和电化学性能的影响 ,结果表明 ,焙烧温度与Li/Mn比是影响材料电化学性能的关键因素 ,确定了制备Li1+xMn2 O4材料最佳条件为 0≤x≤ 0 .0 5 ,焙烧温度 75 0°C ,所得电池材料首次充放电容量达到 1 2 0mAh/g .循环 5 0次后 ,其充放电容量为 1 1 5mAh/g .     

Oxidative-stability enhancement and charge transport mechanism in glyme-lithium salt equimolar complexes

The oxidative stability of glyme molecules is enhanced by the complex formation with alkali metal cations. Clear liquid can be obtained by simply mixing glyme (triglyme or tetraglyme) with lithium bis(trifluoromethylsulfonyl)amide (Li[TFSA]) in a molar ratio of 1:1. The equimolar complex [Li(triglyme or tetraglyme)(1)][TFSA] maintains a stable liquid state over a wide temperature range and can be regarded as a room-temperature ionic liquid consisting of a [Li(glyme)(1)](+) complex cation and a [TFSA](-) anion, exhibiting high self-dissociativity (ionicity) at room temperature. The electrochemical oxidation of [Li(glyme)(1)][TFSA] takes place at the electrode potential of ~5 V vs Li/Li(+), while the oxidation of solutions containing excess glyme molecules ([Li(glyme)(x)][TFSA], x > 1) occurs at around 4 V vs Li/Li(+). This enhancement of oxidative stability is due to the donation of lone pairs of ether oxygen atoms to the Li(+) cation, resulting in the highest occupied molecular orbital (HOMO) energy level lowering of a glyme molecule, which is confirmed by ab initio molecular orbital calculations. The solvation state of a Li(+) cation and ion conduction mechanism in the [Li(glyme)(x)][TFSA] solutions is elucidated by means of nuclear magnetic resonance (NMR) and electrochemical methods. The experimental results strongly suggest that Li(+) cation conduction in the equimolar complex takes place by the migration of [Li(glyme)(1)](+) cations, whereas the ligand exchange mechanism is overlapped when interfacial electrochemical reactions of [Li(glyme)(1)](+) cations occur. The ligand exchange conduction mode is typically seen in a lithium battery with a configuration of [Li anode|[Li(glyme)(1)][TFSA]|LiCoO(2) cathode] when the discharge reaction of a LiCoO(2) cathode, that is, desolvation of [Li(glyme)(1)](+) and insertion of the resultant Li(+) into the cathode, occurs at the electrode-electrolyte interface. The battery can be operated for more than 200 charge-discharge cycles in the cell voltage range of 3.0-4.2 V, regardless of the use of ether-based electrolyte, because the ligand exchange rate is much faster than the electrode reaction rate.     

钼掺杂Li3V2（PO4）3/C正极材料的制备及其电化学性能研究

以Li2CO3、NH4H2PO4、V2O5和MoO3为原料,柠檬酸为络合剂和碳源,采用溶胶-凝胶法制备了锂离子正极材料Li3MoxV2-x(PO4)3/C(x=0.01,0.02,0.03).X射线衍射(XRD)表明,合成的材料具有单一的单斜晶系结构,空间群为P21/n.扫描电镜(SEM)显示Li3Mo0.02V1.98(PO4)3/C具有均一的表面形貌.恒流充放电测试表明,当x=0.02时,掺杂后的Li3Mo0.02V1.98(PO4)3具有最佳的电化学性能.在1C倍率下,3.0～4.3 V电位区间,Li3Mo0.02V1.98(PO4)3/C的首次放电比容量达到122.3 mAh.g-1,循环50周之后,容量没有衰减的迹象;而当x=0、0.01和0.03时,首次放电比容量仅分别为117.1、115.1和116.0 mAh.g-1.在3C和5C倍率下,样品Li3Mo0.02V1.98(PO4)3/C仍能保持优异的循环稳定性.     

锂离子电池富锂正极材料Li[NixLi1/3-2x/3Mn2/3-x/3]O2(x=1/5, 1/4, 1/3)的合成及电化学性能

通过共沉淀法制备了M(OH)2(M=Mn, Ni)前驱体, 并与LiOH混合, 合成了锂离子电池富锂正极材料Li[NixLi1/3-2x/3Mn2/3-x/3]O2, 采用XRD、SEM和充放电实验对其进行表征. 研究结果表明, Li, Ni, Mn原子在M层中呈有序分布, 形成超结构; 富锂正极材料由亚微米的一次粒子团聚组成1~3 μm颗粒; 在2.0~4.8 V电位范围内, 充放电电流密度为10 mA/g时, 富锂正极材料表现出很高的可逆比容量, 达到200~240 mA·h/g, 同时具有良好的循环可逆性能.     

Prospect and Reality of Concentration Gradient Cathode of Lithium-ion Batteries

Li[NixMnyCoz]O2 cathodes are currently the most practicable materials in the timing of developing high-performance rechargeable batteries for next-generation technologies.With the ever-growing demand for energy density,a significant breakthrough has been achieved by the controllable concentration design forming core-shell and concentration gradient structures to push Li[NixCoyMnz]O2 toward higher energy density,longer lifetime and safety.Herein,we review the recent progress on advanced concentration gradient cathode materials.Furthermore,we prospect that this novel approach will continuously extend its advantages in developing extremely fast charging and Co-free cathode materials in the near future.     

钼掺杂磷酸钒锂正极材料的制备及其电化学性能研究

以Li2CO3,NH4H2PO4,V2O5和MoO3为原料,柠檬酸为络合剂和碳源,采用溶胶凝胶法制备了锂离子正极材料Li3MoxV2-x(PO4)3/C (x = 0.01, 0.02和0.03). X射线衍射（XRD）表明,合成的材料具有单一的单斜晶系结构,空间群为P21/n. 扫描电镜（SEM）显示Li3Mo0.02V1.98(PO4)3/C具有均一的表面形貌。恒流充放电测试表明,当x = 0.02时,掺杂后的Li3Mo0.02V1.98(PO4)3具有最佳的电化学性能. 在1C倍率下,3.0 ~ 4.3 V电位区间,Li3Mo0.02V1.98(PO4)3/C的首次放电比容量达到122.3 mAh?g-1,循环50周之后,容量没有衰减的迹象;而当x = 0, 0.01和0.03时,首次放电比容量仅分别为117.1 mAh?g-1,115.1 mAh?g-1和116.0 mAh?g-1. 在3C和5C倍率下,样品Li3Mo0.02V1.98 (PO4)3/C仍能保持优异的循环稳定性.     

锂离子电池正极材料Li2FeSiO4/C的改性研究

采用改进的溶胶-凝胶法合成了Li2Fe1-xMnxSiO4/C(x=0, 1/4, 1/3, 1/2)复合材料. 用X射线衍射(XRD)、拉曼光谱和扫描电子显微镜(SEM)对材料的结构和形貌进行了表征. 通过恒流充放电对材料的电化学性能进行了测试. 结果表明, 在室温、1.5~4.8 V电压范围内, 于C/16倍率下进行充放电测试时, Li2Fe3/4Mn1/4SiO4/C具有较高的首次放电比容量(201.0 mA·h/g), 具有良好的电化学性能.     

Resonant inelastic X-ray scattering and X-ray absorption spectroscopy on the cathode materials LiMnPO4 and LiMn0.9Fe0.1PO4--a comparative study

We present a study of the charge-state behavior of the Li-ion battery cathode materials Li(x)MnPO(4) and Li(x)Mn(0.9)Fe(0.1)PO(4) using X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS). A set of six identical battery cathodes for each material have been cycled and left in different charge states in the range of x = 0.2…1.0 before disassembly in an Ar glove box. Unexpectedly, we find that the Mn 3d-bands are almost inert to the delithiation process, suggesting that Mn ions participate to a very small extent in the charge compensation process. In Li(x)Mn(0.9)Fe(0.1)PO(4) the Fe 3d-band shows much more response to delithiation than the Mn 3d-band. The O 2p-band hybridizes with the bands of the other ions in Li(x)MnPO(4) and Li(x)Mn(0.9)Fe(0.1)PO(4) and thus, indirectly, carries useful information about the effects of delithiation at all ion sites. We conclude that the redox reactions during lithiation/delithiation of these materials are complex and involve repopulation of charges for all constituent elements.     

Li-O2 battery with a dimethylformamide electrolyte

Stability of the electrolyte toward reduced oxygen species generated at the cathode is a crucial challenge for the rechargeable nonaqueous Li-O(2) battery. Here, we investigate dimethylformamide as the basis of an electrolyte. Although reactions at the O(2) cathode on the first discharge-charge cycle are dominated by reversible Li(2)O(2) formation/decomposition, there is also electrolyte decomposition, which increases on cycling. The products of decomposition at the cathode on discharge are Li(2)O(2), Li(2)CO(3), HCO(2)Li, CH(3)CO(2)Li, NO, H(2)O, and CO(2). Li(2)CO(3) accumulates in the electrode with cycling. The stability of dimethylformamide toward reduced oxygen species is insufficient for its use in the rechargeable nonaqueous Li-O(2) battery.     

锂离子电池正极材料Li_2MnSiO_4固体核磁共振谱研究

应用水热-溶胶凝胶法合成了Li2MnSiO4正极材料.由XRD、FTIR、固体NMR及恒流充放电等方法表征、分析样品的相组成、晶体结构和电化学性能.结果表明,合成的样品主相为Li2MnSiO4,同时存在少量Li2CO3杂质.该材料的首次放电容量可达190mAh·g-1,但在充放电循环过程中由于结构坍塌、分解导致其容量衰退明显.