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LiMn2O4的湿法合成及锰的光度法测定研究 总被引:2,自引:0,他引:2
The LiMn2O4 spinel was prepared by wet method using Li2CO3, Mn(CH3COO)2·4H2O and CO2 as raw ma-terials. The products were measured by TG/DTA, XRD, IR. The results Showed that the sample calcined at 800℃ for 10h was well crystallized monophase product. The contents of Mn(Ⅲ) and Mn(Ⅳ) of LiMn2O4 spinel were determined simultaneously by spectrophotometric analysis with pyrophosphoric acid. 相似文献
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锂离子电池具有比能量高、功率大、使用寿命长、无记忆效应、性能价格比高等优点,从而成为可充式电源的主要选择对象.锰由于资源丰富、价廉、环境友好等优点,使锰酸锂(LiMn2O4)成为最有希望取代钴酸锂的正极材料.但锰酸锂的放电容量相对较低,结构欠稳定,容量衰减严重,作为正极材料还无法与钴酸锂相比,近年来做了大量的研究工作以改善它的电化学性能[1~6].最近Youngjoon Shin等研究发现[7]用少量的Li与Ni共同替代LiMn2O4中的Mn得到的LiMn2-2yLiyNiyO4的电化学性能要优于单元素替代的LiMn2-xMxO4(M=Li,Cr,Fe,Co,Ni)的电化学性能. 相似文献
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Li4Ti5O12溶胶-凝胶法合成及其机理研究 总被引:15,自引:0,他引:15
The precursors of Li4Ti5O12 were prepared from tetrabutyl titanate and lithium acetate by sol-gel process. The Li4Ti5O12 samples were synthesized by calcining the gel precursors at 400~900 ℃ in air for 6~20 h. Its reaction mechanism was investigated by infrared spectroscopy(IR), thermogravimetry(TG) and X-ray diffraction(XRD). The effects of sinter-temperature, calcination-time and thermal-treatment for the products were discussed. The samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM). The results showed that the single-phase products were obtained by calcining the gel precursors at 800 ℃ in air for 20 h, the sinter-temperature was lower than that of solid-state method, the particles were narrowly distributed, well crystallized with a size range from 0.3μm to 0.5 μm. 相似文献
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反尖晶石LiNiVO4的湿法低温合成 总被引:1,自引:0,他引:1
LixMn2O4正尖晶石化合物作为锂离子电池正极材料,由于其具有三维网络隧道结构而使电池呈现充放电电压高、 比容量大、 循环性能好和立方结构稳定等特点.Tarascon[1]认为,在LiMn2O4中若阳离子混合度越大,进入16d位置的Li+越多,Li+从16d位置移出将会使电池电压升高.但由于LixMn2O4中阳离子混合度不超过10%,因而限制了该材料的高电位及高电位峰的容量.反尖晶石化合物LiNiVO4的阳离子混合度可达到100%,因而会具有更高的电位(vs.Li). 相似文献
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The vanadates of LiNi1-xMxVO4(M=Fe,Co,Ni) containing VO4 tetrahedrons were synthesized by soft chemical method through a new mild liquid route. The samples sintered at 450℃ for 3h and at 650℃ for 3h are named for LT-LiNiVO4 and for MT-LiNi1-xMxVO4 respectively. All of the products were measured by X-ray diffraction, IR and Raman spectra respectively. In comparison with IR spectra of V2O5 and NiO, the LT-LiNiVO4 has a strong and broad IR absorption band of VO4 tetrahedrons located at 600~850cm-1 with three small splitting peaks corresponding to the asymmetry stretching vibrations of V-O bonds. The results of IR and Raman spectra for MT-LiNi1-xMxVO4 show that the cations of Ni2+, Co2+, Fe2+ have the influences on the frequency shifts of the V-O vibrations. 相似文献
7.
气敏材料Cd2V2O7的制备和性能 总被引:7,自引:0,他引:7
用水热氧化法制备出γMn2O3粉末,并在不同温度下进行烧结.采用XRD,TEM,XPS,IR及紫外分光光度法等表征产物.结果表明,未烧结产物即为单相纳米晶,大部分近似球形,有轻微团聚.产物于空气中100~550℃范围内烧结时热稳定性好.随烧结温度的升高粉末的平均粒子尺寸增大,产物中锰以Mn(Ⅲ)状态存在. 相似文献
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层状LiCo1/3Ni1/3Mn1/3O2正极材料的合成及电化学性能研究 总被引:13,自引:0,他引:13
采用液相法在800 ℃空气中烧结20 h合成出层状LiCo1/3Ni1/3Mn1/3O2正极材料。通过XRD、IR、SEM、XPS和电化学性能测试考察了产物的组成、结构、形貌及电化学性能。结果表明,所合成的LiCo1/3Ni1/3Mn1/3O2为六方单相,层状结构发育完善;产物呈球形且粒度小,分布窄,平均粒径为0.3 μm。以1 mA·cm-2的电流密度,在2.7~4.3 V区间进行充放电测试,前4周的充放电比容量分别为168/160 mAh·g-1、169/162 mAh·g-1、165/160 mAh·g-1、163/158 mAh·g-1,循环性能优良。循环伏安实验表明,该材料在3.9 V附近出现了一对对称性好的氧化还原峰。 相似文献
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预氧化固气法合成LiNiO2的研究 总被引:1,自引:0,他引:1
LiNiO2 was prepared by reaction of stoichiometric amounts of thoroughly-mixed LiOH·H2O and preoxidation nanometer-scale Ni3O2(OH)4 powders in O2 at the temperature of 700℃ for 6h. The products were tested by XRD, XPS, SEM and electrochemistry methods. It was shown that product was LiNiO2 single-phase, and the valence of nickel was +3; the average size of it was 40nm; its initial charge specific capacity is 168mAh·g-1 and the coulomb efficiency is 90%; the second charge specific capacity is 160mAh·g-1 and the coulomb efficiency is 96%. 相似文献