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QIU Chengguang LIU Lina DU Fei YANG Xu WANG Chunzhong CHEN Gang WEI Yingjin 《高等学校化学研究》2015,31(2):270-275
A series of LiMn2O4/LiFePO4 blend cathodes was prepared by hand milling and ball milling in order to compensate the disadvantage of spinel LiMn2O4 and olivine LiFePO4. The morphologies of the blends were studied by scanning electron microscopy, and their electrochemical properties were studied by charge-discharge cycling, cyclic voltammetry and electrochemical impedance spectroscopy. It is easy to obtain uniform LiMn2O4/LiFePO4 blends by the hand milling technique, while significant particle agglomeration is caused by the ball milling technique. When the LiMn2O4:LiFePO4 mass ratio is 1:1, the nano-sized LiFePO4 powders not only uniformly cover the micron-sized LiMn2O4 particles but also effectively fill in the cavities of the LiMn2O4 space. Such morphology offers a good electrical contact and a high tap density, which leads to a high discharge capacity and good cycle stability. 相似文献
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Synthesis and Electrochemical Performance of Spinel LiMn2O4—x(SO4)x Cathode Materials 总被引:1,自引:0,他引:1
IntroductionInrecentyears ,withthedevelopmentofallsortsofcellularphones ,camcorders ,laptopcomputers ,thelithium ionsecondarybatteriesbasedontheuseoflithi um manganese oxideLiMn2 O4 1,2 haveattractedmuchat tention .ButtheLiMn2 O4 cathodematerialhasadisad vantageof… 相似文献
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锂离子电池具有比能量高、质量轻、体积小、电压高、安全性好和无记忆效应等特点,而正极材料是其研究的重点.采用溶胶-凝胶法合成了锂离子电池的正极材料,结果表明,其初始容量高,循环性能理想,并且整个合成过程也较为简单,合成的温度相对较低,样品的颗粒比较均匀. 相似文献
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WANGChun-zhong GONGJie LIUWei WEIYing-jin CHENGang 《高等学校化学研究》2003,19(3):344-346
A Raman study was carried out for LiMnzO4, which was synthesized via the mixture of Mn3O4 and LiNO3 sintered at different temperatures. It is shown that there are two kinds of Raman spectra for LiMn2O4 at different sintering temperatures, while the X-ray diffraction patterns of LiMnzO4 sintered at different temperatures are the same. Five Raman bands observed for the materials sintered below 500 ℃ are consistent with the theoretical prediction for spinel structure based on the group theory. Only two Raman bands were observed for the materials sintered at temperatures higher than 500 ℃. The best preparation condition for obtaining a good spinel LiMn2O4 is suggested based on the Raman study. 相似文献
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尖晶石LiMn2O4中锂离子嵌入脱出过程的电化学阻抗谱研究 总被引:1,自引:0,他引:1
运用电化学阻抗谱(EIS)研究了尖晶石LiMn2O4电极的首次充放电过程. 发现EIS谱高频区域拉长压扁的半圆是由两个半圆相互重叠而成的, 分别归属于与锂离子通过固体电解质相界面膜(SEI膜)的迁移和与尖晶石LiMn2O4材料的电子电导率相关的特征. 通过选取适当的等效电路, 对实验所得的电化学阻抗谱数据进行拟合, 获得尖晶石LiMn2O4电极首次充放电过程中SEI膜电阻、电子电阻和电荷传递电阻等随电极极化电位变化的规律. 根据研究结果提出了嵌锂物理机制模型. 相似文献
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尖晶石LiMn2O4锂充放电池的电化学研究 总被引:6,自引:1,他引:6
本文报导尖晶石型LiMn2O4化合物的制备方法,用循环伏安法和交流阻抗技术研究了Li/有机电解液/LiMn2O4电池的电化学行为,用分形理论首次考察和进一步讨论电极材料的阻抗行为随锂离子嵌入或脱嵌电极时的变化。 相似文献
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合成条件对尖晶石LiMn_2O_4的电化学性能的影响 总被引:6,自引:0,他引:6
以Li2 CO3、LiOH、LiNO3以及电解MnO2 (EMD)作原料 ,用固相反应法合成了尖晶石LiMn2 O4 .结果表明 ,反应物种类及合成条件对LiMn2 O4 的电化学性质有很大的影响 .其中以LiNO3和EMD为合成原料制得的LiMn2 O4 性能最佳 .其制备条件分两步 :先在 2 80℃加热 6h ,使熔融的LiNO3渗入EMD微孔 ,然后在 75 0℃下焙烧合成 相似文献
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Li3PO4包覆LiMn2O4正极材料的结构表征和电化学性能 总被引:1,自引:0,他引:1
采用共沉淀法在尖晶石LiMn2O4颗粒表面包覆Li3PO4.XRD、SEM研究结果表明,包覆后的材料仍为尖晶石结构,粒径均匀.电化学性能测试表明,Li3PO4包覆层的存在,减少了正极材料与电解液的直接接触,抑制了高温下电解液对LiMn2O4材料的侵蚀,从而有效改善了高温下材料的循环性能.在40℃时,包覆样品的比容量衰减率都低于未包覆样品,其中包覆1%Li3PO4的样品的初始比容量为110.4mAh/g,50次循环后比容量为84.1mAh/g. 相似文献
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Synthesis of Single‐Crystalline Spinel LiMn2O4 Nanorods for Lithium‐Ion Batteries with High Rate Capability and Long Cycle Life 下载免费PDF全文
Xiuqiang Xie Dr. Dawei Su Dr. Bing Sun Jinqiang Zhang Prof. Dr. Chengyin Wang Prof. Dr. Guoxiu Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(51):17125-17131
The long‐standing challenge associated with capacity fading of spinel LiMn2O4 cathode material for lithium‐ion batteries is investigated. Single‐crystalline spinel LiMn2O4 nanorods were successfully synthesized by a template‐engaged method. Porous Mn3O4 nanorods were used as self‐sacrificial templates, into which LiOH was infiltrated by a vacuum‐assisted impregnation route. When used as cathode materials for lithium‐ion batteries, the spinel LiMn2O4 nanorods exhibited superior long cycle life owing to the one‐dimensional nanorod structure, single‐crystallinity, and Li‐rich effect. LiMn2O4 nanorods retained 95.6 % of the initial capacity after 1000 cycles at 3C rate. In particular, the nanorod morphology of the spinel LiMn2O4 was well‐preserved after a long‐term cycling, suggesting the ultrahigh structural stability of the single crystalline spinel LiMn2O4 nanorods. This result shows the promising applications of single‐crystalline spinel LiMn2O4 nanorods as cathode materials for lithium‐ion batteries with high rate capability and long cycle life. 相似文献
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以商业微米级锰酸锂(LiMn2O4)为正极,钛酸锂(Li4Ti5O12)为负极,分别与商业活性炭(AC)复合,组装成软包装电池电容样品并进行电化学测试。测试结果表明:当样品正负极均复合AC时,其电化学性能要优于只有正极复合AC和未复合AC的样品。其中,正负极活性炭复合比例为5 wt.%,负极与正极的理论容量比(N/P)为1.01时,电池电容样品拥有良好的倍率性能,且其在0.5 C时的放电比容量为56.4 mAh/g,5 C时的容量保持率为0.5 C的72.2%。此外,与未复合AC的样品相比,单体在5 C倍率下经2000次循环后的容量保持率仍有77.5%,远高于前者的30.4%。 相似文献
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Journal of Thermal Analysis and Calorimetry - A series of LiMn2O4 samples with nominal Li/Mn molar ratio=1/2 has been synthesized at 700 and 750°C by the ceramic procedure from Mn2O3 and... 相似文献
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尖晶石LiMn_2O_4的表面改性研究 总被引:10,自引:0,他引:10
采用溶胶_凝胶法合成尖晶石LiMn2 O4 ,并以LiCoO2 对其进行包覆 ,用XRD、SEM、EPMA等方法对修饰的尖晶石结构和性能进行研究 .结果表明 ,经包覆的LiMn2 O4 在 70 0℃焙烧 10h所得的晶粒是表层富含Co的立方尖晶石 ,而且晶粒中Co3+的含量呈现出从表到里递减的梯度分布 .以该材料作锂离子电池正极 ,虽初始容量稍有降低 ,但能有效地降低Mn2 +在电解质中的溶解 ,而且对Jahn_Teller效应有一定的抑制作用 ,包覆的LiMn2 O4 尖晶石正极材料比未包覆的有更好的循环性能 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(31):9254-9258
The utilization of CO2 in Li‐CO2 batteries is attracting extensive attention. However, the poor rechargeability and low applied current density have remained the Achilles’ heel of this energy device. The gel polymer electrolyte (GPE), which is composed of a polymer matrix filled with tetraglyme‐based liquid electrolyte, was used to fabricate a rechargeable Li‐CO2 battery with a carbon nanotube‐based gas electrode. The discharge product of Li2CO3 formed in the GPE‐based Li‐CO2 battery exhibits a particle‐shaped morphology with poor crystallinity, which is different from the contiguous polymer‐like and crystalline discharge product in conventional Li‐CO2 battery using a liquid electrolyte. Accordingly, the GPE‐based battery shows much improved electrochemical performance. The achieved cycle life (60 cycles) and rate capability (maximum applied current density of 500 mA g−1) are much higher than most of previous reports, which points a new way to develop high‐performance Li‐CO2 batteries. 相似文献
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MENG Yujia LIU Xiaoyang LIU Li LI Benxian ZHAO Xudong FENG Likun WANG Yanxiang WANG Xiaofeng 《高等学校化学研究》2015,31(5):820-824
LiMn2O4 nano-wires with ideal size distribution were readily synthesized by flux method. Samples prepared conventionally were used as the comparison references to investigate the effect of flux. The structural, morphological and electrochemical properties of nano-sized materials were examined by powder X-ray diffraction(XRD) analysis, scanning electron microscopy(SEM) and charge-discharge cycling analysis. Results from galvanostatic charge-discharge analysis show that the samples prepared at 700℃ via flux method(FM-700) afford the highest initial discharge capacity of 125.5 mA·h/g between 3.0 to 4.3 V at a rate of 0.2 C. After 50 cycles, a cycling retention of 89.6% is evident. Overall, the LiMn2O4 nano-wires developed in this work seem to be promising cathode materials for lithium ion batteries suitable to different energy-saving settings. 相似文献
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脉冲激光沉积LiMn2O4薄膜的研究 总被引:5,自引:0,他引:5
在氧气氛下采用355nm脉冲激光烧蚀制备了LiMn2O4薄膜,并用四极质谱和发光光谱技术考察了脉冲激光烧蚀过程及环境氧气对薄膜沉积过程的影响.质谱测定结果表明,355nm激光烧蚀LiMn2O4的产物主要有Li+、Mn+等离子和O2、O、LiO2、LiMnO、MnO及锂原子的多聚体等中性产物.不同氧气压下测定的发光光谱表明烧蚀原子在环境氧气氛中存在氧化过程.用循环伏安法和X射线衍射法对薄膜进行了表征. 相似文献