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采用离子束辅助沉积法制备了锂离子电池硅薄膜负极材料,研究了硅薄膜的晶体结构、表面形貌和电化学性能.研究结果表明:硅薄膜是非晶态的结构;非晶态硅薄膜发生嵌脱锂反应的电位分别为0.03 V与0.34 V和0.16 V与0.49 V;硅薄膜表现出很高比容量和充放电效率,其可逆比容量和库仑效率分别为3134.4 mAh/g和87.1%;硅薄膜具有优异的循环性能,在0.5C倍率下200次循环后容量保持率为92.2%.
关键词:
硅薄膜
离子束辅助沉积
锂离子电池
负极材料 相似文献
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二氧化锡由于其低电位和高储钠理论容量以及绿色无毒的优点被认为是最有前途钠离子电池负极材料之一。但其导电性不好,且在嵌/脱钠的过程中会发生体积膨胀,从而导致电池的容量和循环稳定性等电化学性能下降。碳具有良好的导电性,同时能减缓材料在脱/嵌钠过程的体积膨胀,本文采用一步合成制备SnO2/C复合纳米材料,并将其作为钠离子电池的负极材料进行研究。结果发现碳包覆花瓣状SnO2复合材料相比于纯的SnO2具有良好的储钠性能 相似文献
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本文采用固相法制备了纯相LiMn1-xFexPO4/C (x=0.2,0.4,0.6)正极材料,并用X射线衍射(XRD)和扫描电镜(SEM)进行表征,用高精度电池测试系统进行充放电和循环伏安测试.结果表明不同Mn和Fe原子比的电极材料具有很大的性能差异,其中当x=0.4时,材料具有优异的循环稳定性和较高的可逆容量.首次充电容量和放电容量分别达到141.5 mAh/g和125.7 mAh
关键词:
锂离子电池
固相法
1-xFexPO4')" href="#">LiMn1-xFexPO4
正极材料 相似文献
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针对锂离子电池硅及其复合电极材料,采用Cahn-Hilliard型扩散方程与有限变形理论全耦合的电化学-力模型来描述其在循环锂化过程中的扩散和力学相关性问题,构造高效的数值算法,在商用有限元软件平台上实现对该理论的数值求解.在此基础上,研究了硅电极恒流锂化和脱锂过程,基于界面反应动力学,得到电压响应曲线,计算结果整体趋势与实验结果吻合较好,同时预测的应力响应也与实验结果一致,验证了本方法的有效性.其次,研究了中空碳包覆硅负极锂化过程中的电化学与力学行为,计算结果表明,锂化期间中空碳包覆硅负极应力水平明显低于实心硅负极,随锂化的进行,应力差值越来越大,锂化结束时应力值降低约27%,这种应力的缓解提高了整个电极内化学势水平,使得锂离子浓度水平显著提高,更易达到完全锂化状态.同时,数值研究表明应力水平的缓解延缓了中空碳包覆硅负极的容量衰减(容量提升74%),充分显示出该电极良好的电化学性能.本研究揭示了应力对硅复合电极容量影响的作用机制,为将连续介质电化学-力耦合理论应用于实验预测提供了途径并为电极材料设计提供了理论依据. 相似文献
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碳负极材料作为锂/钠离子电池的传统负极材料一直获得广泛的推广和应用,但其仍存在充电时间长、库伦效率低等问题,研究碳负极材料充放电机理是解决这些问题的关键.固体核磁共振(NMR)技术是一种研究固体材料中目标原子所处化学环境以及材料内部结构变化的有效手段.通过测定锂/钠离子电池中6Li、7Li和23Na高速魔角旋转(MAS)条件下的固体NMR谱图,能够清晰获得锂/钠离子电池碳负极脱/嵌过程中的结构变化,以及碳原子与Li/Na的配位情况,从而为碳负极材料的设计及其电化学性能的提升提供充分的理论依据.本文综述了近年来固体NMR技术在锂/钠离子电池碳负极材料研究中的应用以及相关研究进展. 相似文献
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A porous composite anode for lithium ion battery (LIB) was investigated. The composite anode was prepared by electrodepositing Sn?CSb alloy on a template-like electrode and then annealing it in the atmosphere of N2, whereas the porous template-like electrode was obtained by forming a sponge-like porous membrane on a copper foil via a mixed phase inversion process, followed by pre-plating Cu through membrane pores in it. SEM and XRD results showed that composite structure of the anode consisted of electrodeposited Sn?CSb alloy dispersed in a PAN-pyrolyzed conjugated conducting polymer gridding, which was tightly connected with the Cu foil through transition alloy layer formed by heat treatment. Due to its relatively reasonable microcosmic structure, the composite anode presented better cycling performance and specific capacity retention during charging and discharging at diverse rates. When cycled between 0 and 2.0?V (vs Li/Li+) at 0.5?C rate, the reversible charge/discharge capacity of the composite material remained 415 and 414.8?mAh?g?1, respectively, after 30 cycles, corresponding to 82.9% of the capacity retention. When charging and discharging at 2?C rate, the composite material electrode showed 71.7% capacity retention at the 30th cycle. 相似文献
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Silica doped tin oxide composites prepared by a sol gel method have been studied as negative electrode materials for lithium-ion
batteries. The composite powders fired at 500 °C were analysed by means of XRD and SEM and showed that the composite consists
of a blend of crystalline and amorphous structure with different particle size distribution. The electrochemical properties
of this anode material were examined by charge-discharge measurements and cyclic voltammetry. The silica doped tin oxide composite
anode, which was cycled between 0.1 to 2.0 V, showed a reversible capacity of 270 mAh/g.
Paper presented at the International Conference on Functional Materials and Devices 2005, Kuala Lumpur, Malaysia, June 6 –
8, 2005. 相似文献
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《Solid State Ionics》2006,177(15-16):1331-1334
Hard carbon/Li2.6Co0.4N composite anode electrode is prepared to reduce the initial high irreversible capacity of hard carbon, which hinders potential application of hard carbon in lithium ion batteries, by introducing Li2.6Co0.4N into hard carbon. Lithiated Li2.6Co0.4N provides the compensation of lithium in the first cycle, leading to a high initial coulombic efficiency of ca. 100% versus lithium. As-prepared hard carbon/Li2.6Co0.4N composite electrode presents initial capacity of 438 mA h g− 1. A full cell using LiCoO2 cathode and the composite anode shows much higher initial coulombic efficiency and capacity than those of a cell using LiCoO2 and hard carbon anode. This paves the way to reduce the large initial irreversible capacity of hard carbon. 相似文献
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N-doped graphene/SnS composite as high-performance anode materials has been synthesized by a simultaneous solvothermal method using ethylene glycol as solvent. The morphology, structure, and electrochemical performance of N-doped graphene/SnS composite were investigated by transmission electron microscope (TEM), X-ray diffraction (XRD), Raman spectra, Fourier transform infrared (FTIR) spectra, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. The SnS nanoparticles with sizes of 3–5 nm uniformly distribute on the N-doped graphene matrix. The N-doped graphene/SnS composite exhibits a relatively high reversible capacity and good cycling stability as anode materials for lithium ion batteries. The good electrochemical performance can be due to that the N-doped graphene as electron conductor improves the electronic conductivity of composite and elastic matrix accommodates the large volume changes of SnS during the cycles. 相似文献
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The lithium-ion battery is a battery that is being developed to become a repository of energy, particularly for electric vehicles. Lithium titanate (Li4Ti5O12) anodes are quite promising for this application because of its zero-strain properties so it can withstand the high rate. However, the capacity of LTO (Li4Ti5O12) is still relatively low. Therefore, the LTO needs to be combined with other materials that have high capacity such as Si. Silicon has a very high capacity which is 4200 mAh/g, but it has a high volume of the expansion. Nano-size can also help increase the capacity. Therefore composite of LTO/nano Si is made to create an anode with a high capacity and also stability. Nano Si is added with a variation of 1, 5, and 10%. LTO/nano Si composite is characterized using XRD, SEM-EDX, and TEM-EDX. Then, to determine the battery performance, EIS, CV, and CD tests were conducted. From those tests, it is studied that Si improves the conductivity of the anode, but not significantly. The addition of Si results a greater battery capacity which is 262.54 mAh/g in the LTO-10% Si. Stability of composite LTO/nano Si is good, evidenced by the coulomb efficiency at the high rate of close to 100%. 相似文献
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The sulfur resistance and performance of Sr- and Mn-doped yttrium chromite (YSCM)-samaria-doped ceria (SDC) composite material were investigated for potential use as anodes in solid oxide fuel cells (SOFCs). The anode was well adhered to the electrolyte, which was ascribed to their similar coefficient of thermal expansion (TEC). The electro-catalytic activity of YSCM-SDC anodes in yttria-stabilized zirconia (YSZ) electrolyte-supported cells toward hydrogen oxidation was superior to that of the La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCM) anode. Sr depletion in the YSCM structure and the formation of SrSO4 in the presence of sulfur led to performance degradation of the anode. Irreversible and reversible performance degradation suggested that YSCM and SDC played a respective role during the anode deactivation process. The voltage decreased at a rate of 31 mV/h and stabilized at 0.49 V under a 3000 ppm H2S atmosphere. In addition, the sulfur tolerance of YSCM-SDC anode was better than SDC under strictly identical conditions. 相似文献
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The hydrogen storage capacity of MWCNT–TiO2 composite has been evaluated in the present work. The composite has been prepared by means of ultrasonication followed by drop casting on substrates. Morphology, structural and functional group studies of the prepared samples are carried out by transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. Then, the samples are hydrogenated in the hydrogenation chamber as a function of time. Hydrogen storage capacity of the composite sample is found to be 0.9 wt% at 100 °C. Hydrogen uptake of the composite is accounted for the spillover mechanism in CNTs–metal oxide composite. Desorption temperature range, activation energy of desorption, binding energy of hydrogen are determined from thermogravimetric (TG) analysis. 相似文献
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采用Bathocuproine/Ag (BCP/Ag)复合电极代替Ca/Al复合电极, 制备PTB7:PC71BM 作为光敏层的聚合物光伏器件, 并通过改变BCP薄膜厚度来研究BCP/Ag复合电极对于器件光电转换器和稳定性的影响. 研究发现: 在光敏层和金属电极之间插入BCP修饰层后, 器件性能得到了显著的改善, 在BCP厚度为5 nm时, 器件的效率达到了6.82%, 且略高于Ca/Al复合电极的器件效率; 相比于采用Ca/Al复合电极的器件, BCP/Ag复合电极增大了器件的短路电流和外量子效率, 使器件效率得到提高; 同时器件的稳定性得到了显著的改善, BCP/Ag 复合电极器件的衰减速率几乎和未插入BCP的器件衰减速率相同, 相对于Ca/Al复合电极器件大幅提高. 相似文献
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Probing component contributions and internal polarization in silicon-graphite composite anode for lithium-ion batteries with an electrochemical-mechanical model 下载免费PDF全文
Silicon-graphite (Si-Gr) composite anodes are attractive alternatives to replace Gr anodes for lithium-ion batteries (LIBs) owing to their relatively high capacity and mild volume change. However, it is difficult to understand electrochemical interactions of Si and Gr in Si-Gr composite anodes and internal polarization of LIBs with regular experiment methods. Herein, we establish an electrochemical-mechanical coupled model to study the effect of rate and Si content on the electrochemical and stress behavior in a Si-Gr composite anode. The results show that the composites of Si and Gr not only improve the lithiation kinetics of Gr but also alleviate the voltage hysteresis of Si and decrease the risk of lithium plating in the negative electrode. What's more, the Si content is a tradeoff between electrode capacity and electrode volume variation. Further, various internal polarization contributions of cells using Si-Gr composite anodes are quantified by the voltage decomposition method. The results indicate that the electrochemical polarization of electrode materials and the electrolyte ohmic over-potential are dominant factors in the rate performance of cells, which provides theoretical guidance for improving the rate performance of LIBs using Si-Gr composite anodes. 相似文献