共查询到20条相似文献,搜索用时 15 毫秒
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James Manuel Chorong Shin Jou-Hyeon Ahn Jung-Pil Noh Ho-Suk Ryu 《Materials Research Bulletin》2010,45(3):265-268
Doped polyaniline with LiPF6 is electrosprayed onto aluminum foil using electrospinning technique, and evaluated as cathode active material for application in room-temperature lithium batteries. Doping level is characterized using FTIR and UV-vis spectroscopy. In FTIR Spectra, characteristic peaks of PANI are shifted to lower bands as a result of doping which indicates the effectiveness of doping. Doping level is also confirmed by UV-vis spectra. Surface morphology of the cathode is studied using scanning electron microscope. Electrochemical evaluation of the cell using electrosprayed PANI as cathode show good cycling properties. The cell delivers a high discharge value of 142.5 mAh/g which is about 100% of theoretical capacity, and the capacity is lowered during cycle and reached 61% of theoretical capacity after 50 cycles. The cell delivers a stable but lower discharge capacity at higher C-rates. 相似文献
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通过高温固相合成法以MnCO3为锰源、(MgCO3)4·Mg(OH)·5H2O为镁源,葡萄糖为碳源,在氩气气氛下合成二元掺杂Mn、Mg的LiFe0.8Mn0.1Mg0.1PO4/C和LiFePO4/C正极材料,采用X射线衍射(XRD)、扫描电子显微镜(SEM)、红外光谱仪(FT-IR)进行结构表征,通过恒电流充放电实验研究了LiFe0.8Mn0.1Mg0.1PO4/C和LiFePO4/C电化学性能。结果表明,二元掺杂Mn、Mg的LiFe0.8Mn0.1Mg0.1PO4/C呈现橄榄石结构,无杂质产生。与未掺杂的LiFePO4/C相比,掺杂后LiFe0.8Mn0.1Mg0.1PO4/C提高了电导率,0.1C倍率下放电可逆容量为131mAh/g,表现出良好的电化学性能。 相似文献
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Yingbin Lin Ying Lin Ting ZhouGuiying Zhao Yandan HuangYanmin Yang Zhigao Huang 《Materials Chemistry and Physics》2013
LiFePO4/Si composites are synthesized via a simple milling isopropanol mixtures process, and the effects of Si-modification on the electrochemical performances of LiFePO4 are investigated systematically by charge/discharge testing, cyclic voltammograms and AC impedance spectroscopy, respectively. In comparison with the pristine LiFePO4, LiFePO4/Si-nanoparticle shows better cyclability and higher rate capability, especially at elevated temperature. An analysis of the electrochemical measurements indicates that Si incorporation could significantly improve the electrochemical performance at high charge/discharge rate and elevated temperature. Among the investigated samples, (LiFePO4)98/(Si)2 sample shows the best electrochemical performance with 150 mAhg−1 at 0.5C at 60 °C. The enhancement could be mainly attributed to the lower charge-transfer resistance and higher lithium diffusion coefficients. In addition, the dangling bonds of Si and fluorosilica compounds are responsible for suppressing the dissolution of Fe2+ from olivine phase and preventing the rise of the surface resistance and charge transfer resistance. 相似文献
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The electrochemical properties of alpha-MoO3 nanorods, which were synthesized via a solution-based method and following calcination, have been reported as a cathode material for rechargeable lithium batteries. Detailed lithium-insertion process of the material has been conducted by means of cyclic voltammetry, galvanostatic method, and impedance technique, and superior features associated with the nanostructures have been observed. The alpha-MoO3 nanorods exhibited an initial discharge capacity of 271.8 mAh/g under a current density of 0.1 mA/cm2 in the range 1.0 approximately 3.0 V, which nearly approached the theoretical capacity 280 mAh/g. Comparison of the structural and electrochemical characteristics with those of bulk alpha-MoO3 suggests the enhanced electrochemical performance might be related to the rodlike structure and increased edge and corner effects. 相似文献
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通过热分解MnCO3和AgNO3的方法制备了具有Ag包覆结构的MnO微米球。分别采用XRD、SEM和恒流充放电技术考察了其晶体结构、颗粒形貌和电化学性能。分析结果表明,该MnO/Ag复合材料结晶度良好,呈球状,直径约1.2μm,Ag包覆在MnO球体表面。当充放电电流密度为34.8mA/g时,MnO/Ag复合材料的首次库伦效率高达70.0%,初始可逆比容量为805.3mA.h/g,经30周循环后,其放电比容量仍保持在407.8mA.h/g。当电流密度增加到190.5mA/g时,其放电比容量仍有320mA.h/g。 相似文献
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Pengjian Zuo Zhenbo Wang Geping Yin Dechang Jia Xinqun Cheng Chunyu Du Pengfei Shi 《Journal of Materials Science》2008,43(9):3149-3152
Silicon-graphite composites were prepared by mechanical ball milling for 20 h under argon protection. The microstructure and
electrochemical performance of the composites were characterized by X-ray diffraction (XRD), scanning electron microscopy,
and electrochemical experiments. XRD showed that the materials prepared by ball milling were composites consisting of Si and
graphite powders. The composite electrode showed the best performance, especially when annealed at 200 °C for 2 h, which had
a reversible capacity of 595 mAh g−1 and an initial coulombic efficiency of 66%, and still retained 469 mAh g−1 after 40 cycles with about 0.6% capacity loss per cycle. 相似文献
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采用失重法、线性电位扫描、扣式电池放电测试等方法,研究AZ21和AZ31镁合金作为镁锰干电池负极材料时的电化学性能以及电解质添加剂Li2CrO4对其电化学性能的影响。结果表明,作为干电池的负极材料,在Mg(ClO4)2作电解质时,AZ21与AZ31相比,其自腐蚀速率大,开路电压稍高,电池容量和正极材料利用率低;添加少量的Li2CrO4能大大降低AZ21和AZ31合金的自放电速率,其缓蚀作用随Li2CrO4浓度的增加而增加,但当超过0.3%(质量分数)后反而降低;Li2CrO4的添加可提高电池的工作电压、电池容量和正极材料利用率。 相似文献
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用一步固相法合成了斜方锰酸锂,对其进行了表征并确定了前驱体化合物烧结中的转变过程,以及相互化合间的烧结机制.结果表明,随着煅烧温度的升高,杂相减少,生长出主体相斜方锰酸锂.在700℃以上可以生成均一相的层状斜方类球状和棒状锰酸锂颗粒.两种颗粒的粒度分别为1~5μm和5~15μm.在充放电循环中,斜方锰酸锂结构易于向尖晶石结构转变.在2.5~4.5V范围内以20mA/g电流进行充放电循环,斜方锰酸锂的初始充电容量达到247mAh/g,放电容量为133mAh/g,50次循环后,容量保持率为92%. 相似文献
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Solid polymer electrolytes (SPEs) are an excellent alternative to liquid electrolytes due to their non-volatility, low toxicity, and high energy density. In this study, a SPE having the ion transport mechanism decoupled from segmental motion of a polymer based on poly(vinyl alcohol) (PVA) containing the salt lithium trifluoromethane sulfonate (LiCF3SO3, LiTf) has been prepared to overcome the low ionic conductivity of traditional SPEs at room temperature. PVA has a high glass transition temperature (358 K) and good mechanical properties, and despite being atactic, it can crystallize, especially if highly hydrolyzed. From an ac impedance analysis, it was found that the ionic conductivity of the PVA-based SPE increased with increasing salt concentration. In particular, a dramatic increase was observed between 40 and 50 wt% of salt. The ionic conduction mechanism of the PVA-based SPE is proposed based on intensive study using FT-IR spectroscopic measurements, XRD and AFM. Through measurements of linear sweep voltammetry (LSV) and cyclic voltammetry (CV), it is also found that the SPE with PVA and LiCF3SO3 has good electrochemical stability. 相似文献
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Limin Li Yanjing Yang Haijie Shen Zhengzheng Huang Xiaoxia Xiang 《Materials Letters》2010,64(19):2115-361
Nitrogen-containing carbons have been prepared from polyaniline by carbonization and activation. Lithium storage performances of the carbons have been studied by galvanostatic charge/discharge. The carbon without activation shows a first discharge capacity of 729 mAh g− 1, after activation, the capacity improved. The first discharge capacity of the carbon prepared by H3PO4 activation is 1083 mAh g− 1, and that of the carbon prepared by KOH activation is as high as 2201 mAh g− 1, whose reversible capacity is 1027 mAh g− 1. To the carbon prepared by KOH activation, the first coulombic efficiency is just 47%, however, from the second cycle, the coulombic efficiency goes up rapidly to above 90%, the reversible capacity is still as high as 747 mAh g− 1 after 20 cycles. It may be a promising candidate as an anode material for lithium secondary batteries. 相似文献
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《Materials Research Bulletin》2013,48(4):1737-1740
Iron orthovanadate microrods with layered structure have been synthesized by a simple hydrothermal method. The composition and structure of the microrods were investigated by X-ray powder diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. Electrochemical measurements indicated that the microrods maintained high capacity when used as lithium ion battery cathode. As-obtained iron orthovanadate microrods electrode exhibits a stable and reversible capacity of over 250 mAh g−1 at 16 mA g−1 between 1.6 V and 4.7 V after 15 cycles. Detailed investigations reveal that the layered structure may reduce the lithium ion diffusion path and be helpful for stable capacity. 相似文献
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对LiNiO2派生物LiNixCo1-xM0.05O2(M=Al,Mn,Ti)的性能进行了研究.采用了溶胶-凝胶法(Sol-gel)合成了KLiNixCo1-xM0.05O2(M=Al,Mn,Ti),采用XRD表征其晶体结构,均为层状结构;采用扫描电镜(SEM)观察产物的晶体形貌,粉末颗粒细小,粒径约为0.3~0.5μm.充放电测试表明,合成的LoiNixCo1-xAl0.05O2的循环性能比较好,LiNi0.7Co0.25Mn 0.05O2的初始容量较高. 相似文献
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Chromium was incorporated into lithium trivanadate by an aqueous reaction followed by heating at 100 °C. This Cr doped LiV3O8 as a cathode for lithium ion batteries exhibits 269.9 mAh g− 1 at first discharge cycle and remains 254.8 mAh g− 1 at cycle 100, with a charge-discharge current density of 150 mA g− 1 in the voltage range of 1.8-4.0 V. The Cr-LiV3O8 cathode show excellent discharge capacity, with the retention of 94.4% after 100 cycles. These result values are higher than previous reports indicating that Cr-LiV3O8 prepared by our low temperature synthesis method is a promising cathode material for rechargeable lithium ion batteries. The enhanced discharge capacity and cycle stability of Cr-LiV3O8 cathode indicate that chromium atoms promote lithium transfer or intercalation/deintercalation during the electrochemical cycles and improve the electrochemical performances of LiV3O8 cathode. 相似文献
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采用固相反应法制备了LiFe0.7Mn0.3PO4-C复合材料。用x射线衍射、扫描电镜和电化学测试对符合材料的结构、形貌和电化学性能进行了研究。结果表明,LiFe0.7Mn0.3PO4-C具有单一的橄榄石结构,碳的加入影响了LiFe0.7Mn0.3O4的表面形貌。LiFe0.7Mn0.3PO4-C复合材料的颗粒大小在100-200nm之间,碳均匀地包覆在LiFe0.7Mn0.3O4颗粒的表面.与LiFe0.7Mn0.3O4相比,LiFe0.7Mn0.3PO4-C复合材料具有更高的可逆比容量、更好的循环性能:0.1C放电时LiFe0.7Mn0.3O4-C复合材料的可逆容量达到141mAh/g,60次循环后平均每次循环的容量损失只有0.19%,而相同条件下60次循环后LiFe0.7Mn0.3O4平均每次循环的容量损失为0.53%,表明碳的加入有效地改善了LiFe0.7Mn0.3O4的电化学性能。 相似文献