共查询到17条相似文献,搜索用时 70 毫秒
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锂离子电池正极材料尖晶石LiMn204的研究现状 总被引:4,自引:0,他引:4
从制备方法,循环性能,比容量,高温性能等方面对近年来有关LiMn204尖晶石的研究作一综述;讨论合成方法,反应条件,尖晶石的晶体结构及改性对正极材料性能的影响,并预示该类正极材料今后的研究方向。 相似文献
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采用喷雾热解的方法合成了单相的尖晶石LiMn2O4的颗粒,结构研究结果表明用这种喷雾造粒的方法可以得到颗粒细小匀的LiMn2O4粉体,其组装的电池具有良好的电化学容量和循环性能,表明这是一种可推广的合成锂离子电池正极材料LiMn2O4粉体的方法。 相似文献
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稀土掺杂对锂离子电池正极材料LiMn2O4结构及电性能的影响 总被引:19,自引:5,他引:19
利用微波加热技术合成稀土掺杂基锂离子电池正极材料LiMn2-xRExO4(RE=Y,Nd,Gd,Ce),通过XRD、循环伏安及恒电漉充放电测试研究了稀土掺杂离子对合成正极材料结构及电化学性能的影响。XRD测试结果表明,合适的掺杂量可以起到扩展锂离子脱嵌通道和稳定骨架结构的作用,稀土离子的引入可以部分取代原有的三价锰离子,由于稀土离子的离子半径较三价锰离子大,因此稀土掺杂锰酸锂材料的晶胞参数比未掺杂材料大,在一定程度上扩充了锂离子迁移的三维通道,更有利于锂离子的嵌入与脱嵌;循环伏安及恒电漉充放电测试结果表明稀土掺杂有效提高了LiMn2O4材料的电化学循环可逆性及循环稳定性。 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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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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A series of Sc3+-doped spinel lithium manganese oxides Li1+xScyMn2-yO4(y=0.01, 0.02, 0.06, and 0.10)were synthesized by solid state reaction using LiOH·H2O, MnO2, and Sc2O3 as starting materials. The results of powder X-ray diffraction indicated that the doped Li1+xScyMn2-yO4 maintain the cubic structure of spinel phase Fd3m. The electrochemical properties were characterized by electrochemical methods. The initial discharge capacity reached 135 mAh/g and the capacity fading rate was less than 2% after 40 cycles. The spinel phase was well preserved after 40 cycles. The doping of Sc3+ effectively improved the cycleability of spinels, and was a promising way for the improvement of spinel LiMn2O4 cathode materials. 相似文献
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Al掺杂对尖晶石型LiMn2O4结构及循环性能的影响 总被引:1,自引:0,他引:1
用柠檬酸作为螯和物的载体,采用溶胶-凝胶法合成了A l3 掺杂的锂离子电池正极材料L iA lxMn2-xO4。XRD,SEM研究表明,于800℃煅烧可获得单一尖晶石结构的物相;随着A l3 掺入量的增加,L iA lxMn2-xO4的晶格常数变小,晶格更趋于完整,有利于抑制因锂的反复脱嵌而造成的结构破坏。x=0.05时,首次放电容量为103.8 mAh.g-1,25次循环后放电容量还有100.6 mAh.g-1,容量衰减仅为3.08%。 相似文献
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混合超级电容器AC/LiMn2O4体系的电化学性能 总被引:2,自引:0,他引:2
对AC/LiMnO4体系混合电容器进行研究,以活性炭(AC)为负极材料,尖晶石结构的LiMn2O4为正极材料,Li2SO4为电解液。该体系的原理与锂离子电池很相似,从本质上说属于一种特殊的锂离子电池。改变正负极的质量配比,根据其电化学性能确定了该体系最佳的正负极质量配比。对不同电解液浓度的电容器进行不同电流密度充放电测试,发现电解液浓度增加,会使容量和大电流性能得到明显改善,极化电阻的增大会大大降低放电电压平台。实验表明该体系具有较高的能量密度和功率密度,同时保持了良好的循环性能。 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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Xiang Ming He Jian Jun Li Yan Cai Yaowu Wang Jierong Ying Changyin Jiang Chunrong Wan 《Journal of Solid State Electrochemistry》2005,9(6):438-444
A novel process is proposed for synthesis of spinel LiMn2O4 with spherical particles from the inexpensive materials MnSO4, NH4HCO3, and NH3H2O. The successful preparation started with carefully controlled crystallization of MnCO3, leading to particles of spherical shape and high tap density. Thermal decomposition of MnCO3 was investigated by both DTA and TG analysis and XRD analysis of products. A precursor of product, spherical Mn2O3, was then obtained by heating MnCO3. A mixture of Mn2O3 and Li2CO3 was then sintered to produce LiMn2O4 with retention of spherical particle shape. It was found that if lithium was in stoichiometric excess of 5% in the calcination of spinel LiMn2O4, the product had the largest initial specific capacity. In this way spherical particles of spinel LiMn2O4 were of excellent fluidity and dispersivity, and had a tap density as high as 1.9 g cm–3 and an initial discharge capacity reaching 125 mAh g–1. When surface-doped with cobalt in a 0.01 Co/Mn mole ratio, although the initial discharge capacity decreased to 118 mAh g–1, the 100th cycle capacity retention reached 92.4% at 25°C. Even at 55°C the initial discharge capacity reached 113 mAh g–1 and the 50th cycle capacity retention was in excess of 83.8%. 相似文献
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