共查询到19条相似文献,搜索用时 93 毫秒
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以纳米TiO2和LiNO3为原料,尿素为燃料,燃烧法合成了锂离子电池负极材料Li4Ti5O12. 利用XRD、SEM和恒电流充放电、循环伏安和交流阻抗对其进行表征. 结果表明,预设炉温850℃,尿素与锂摩尔比1,焙烧8 h,制备得到平均粒径小于500 nm、粒度分布均匀的纯相尖晶石型结构Li4Ti5O12,并具有良好的电化学性能,具有1.5 V充放电平台,在0.1 C倍率下(1 C=170 mA·h/g),其首次充放电容量达到168 mA·h/g,经过100次循环后放电比容量仍有162 mA·h/g,容量保持率96.4%. 相似文献
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以 Li2CO3、TiO2、Ni(CH3COO)2.4H2O为原料,采用固相法制备尖晶石型Li4Ti4.9Ni0.1O12锂离子负极材料。通过X射线衍射(XRD)、扫描电镜(SEM)、恒流充放电测试以及交流阻抗等技术对材料进行结构、形貌及电化学性能测试。研究结果表明,制备出的Li4Ti4.9Ni0.1O12材料无杂质相,颗粒大小均匀,在0.5C下首次放电比容量为173.3mAh g-1,库伦效率为97.4%,50次循环后,材料放电比容量为163.4mAh g-1,容量保持率为94.3%。 相似文献
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以Li_2CO_3、TiO_2、Ni(CH_3COO)_2×4H_2O为原料,采用固相法制备尖晶石型Li_4Ti_(4.9)Ni_(0.1)O_(12)锂离子负极材料。通过X射线衍射(XRD)、扫描电镜(SEM)、恒流充放电测试以及交流阻抗等技术对材料进行了结构、形貌表征及电化学性能测试。结果表明,制备的Li_4Ti_(4.9)Ni_(0.1)O_(12)材料无杂相,颗粒大小均匀,在0.5 C下首次放电比容量为173.3 mA×h/g,库伦效率为97.4%,50次循环后,材料的放电比容量为163.4 mA×h/g,容量保持率为94.3%。 相似文献
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针对Li4Ti5O12导电性和倍率性能差的缺陷,以PEG为碳源采用溶胶-凝胶法制备出电池负极材料Li4Ti5O12/C,考察不同分子量聚乙二醇PEG(400、600、1000)做碳源制备的Li4Ti5O12/C复合材料电化学性能的优劣,采用热重分析仪(TG)、X射线衍射仪(XRD)、扫描电镜(SEM)、透射电镜(TEM)、恒流充放电、倍率放电、交流阻抗(EIS)等方法对材料进行了结构表征和电化学性能测试。结果表明:以PEG1000为碳源时得到的Li4Ti5O12/C,0.1C下首次放电比容量为143.5 mA·h·g-1,2C的倍率下仍然保持了105 mA·h·g-1的比容量,容量保持率达到73.17%,并且此材料有最小的电阻,在大电流条件下有良好的电化学性能。 相似文献
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描述了Li4Ti5O12的晶体结构、性能、合成方法以及掺杂改性的研究现状。Li4Ti5O12作为锂离子电池的负极材料,在Li嵌入和脱出的过程中,其晶型不发生改变,体积变化小于1%,被称之为“零应变材料”。目前主要合成方法为固相反应法和溶胶-凝胶法。 相似文献
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Dan Wang Chunming Zhang Yaoyao Zhang Jin Wang Dannong He 《Ceramics International》2013,39(5):5145-5149
La-doped Li4Ti5O12 was successfully synthesized from Li2CO3, La2O3 and tetrabutyl titanate by a simple ball milling assisted modified solid-state method. The impact of La-doping on crystalline structure, particle size, morphology and electrochemical performance of Li4Ti5O12 was investigated. The samples were characterized by XRD, SEM, galvanostatically charge–discharge and electrochemical impedance spectroscopy. The results demonstrated that the in-situ coated and ball-milling method could decrease the particle size and prevent the aggregation of Li4Ti5O12. La-doping obviously improved the rate capability of Li4Ti5O12 via the generation of less electrode polarization and higher electronic conductivity. Li3.95La0.05Ti5O12 exhibited a relatively excellent rate capability and cycling stability. At the charge–discharge rate of 0.5 C and 40 C, its discharge capacities were 176.8 mAh/g and 54.7 mAh/g. After 10 cycles, fairly stable cycling performance was achieved without obvious capacity fade at 0.5 C, 1 C, 2 C, 5 C, 10 C, 20 C and 40 C. In addition, compared to Li4Ti5O12, Li3.95La0.05Ti5O12 almost did not have the initial capacity loss. It indicated that Li3.95La0.05Ti5O12 was a promising candidate material for anodes in Li-ion battery application. 相似文献
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以Li2CO3、锐钛矿TiO2和石墨烯为原料,采用固相球磨及喷雾干燥相结合的方法制备钛酸锂和钛酸锂/石墨烯复合负极材料。用X射线衍射(XRD)、拉曼光谱、扫描电子显微镜(SEM)表征了样品的晶体结构及形貌。通过恒流充放电测试样品的电化学性能,考察不同石墨烯添加量对钛酸锂材料电化学性能的影响。当石墨烯添加量质量分数为1%时,钛酸锂/石墨烯复合负极材料(LTO-G-2)具有优异的倍率性能及循环稳定性。在0.2C、0.5C、1C、3C、5C和10C倍率下的充电比容量为172.9mA·h/g、165.7mA·h/g、163.5mA·h/g、157.4mA·h/g、154.0mA·h/g和143.5mA·h/g。5C倍率下经历200次循环,容量保持率为94.8%。循环伏安测试(CV)表明LTO-G-2样品的极化程度是最小的。交流阻抗测试(EIS)结果显示LTO-G-2的电荷转移阻抗(69.6Ω)小于纯的钛酸锂的电荷转移阻抗(140.5Ω)。 相似文献
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《Ceramics International》2016,42(14):15464-15470
The TiN coated Li4Ti5O12 (LTO) submicrospheres with high electrochemical performance as anode materials for lithium-ion battery were synthesized successfully by solvothermal method and subsequent nitridation process in the presence of ammonia. The XRD results revealed that the crystal structure of LTO did not change after thermal nitridation process. The submicrospheres morphology of LTO and TiN film on the surface of LTO submicrospheres were characterized by FESEM and HRTEM, respectively. XPS result confirmed that a small amount of Ti changed from Ti4+ to Ti3+ after nitridation process, which will increase the electronic conductivity of LTO. Electrochemical results showed that electrochemical performance of TiN coated LTO anode materials compared favorably with that of pure LTO. Also its rate capability and cycling performance were apparently superior to those of pure LTO. The reversible capacity of TiN-LTO is 105.2 mA h g−1 at a current density of 10 C after 100 cycles and maintain 92.9% of its initial discharge capacity, while that of pure LTO is only 83.6 mA h g−1 with a capacity retention of 90.3%. Even at 20 C, the discharge capacity of TiN coated LTO sample is 101.3 mA h g−1, compared with 77.3 mA h g−1 for pristine LTO in the potential range 1.0–2.5 V (vs. Li/Li+). 相似文献
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Lu Zhang Jian-Dong Zhang Xian Luo Yong-Fu Long Xin Xue Yue Yin Ben-Jun Xu 《Ceramics International》2021,47(4):4729-4736
Low capacity and rate performance are important factors restricting the development of Li4Ti5O12 (LTO). The addition of an appropriate amount of polyethylene glycol (PEG) is an effective method to increase the capacity and rate performance of LTO anode material. In this study, LTO anode material was synthesised by the sol–gel method using PEG as a template agent. X-ray diffraction (XRD) results show that the addition of PEG can improve the crystallinity of the material and retain the spinel lattice type of LTO. Scanning electron microscopy (SEM) results show that the addition of an appropriate amount of PEG can promote the formation of a more uniform and much finer morphology. The results of high-resolution transmission electron microscopy (HRTEM) show that the material with PEG had good crystallinity. The charge and discharge data verify that the electrochemical performance of the material could be improved by adding PEG. P2-LTO exhibits a smaller particle size, largest capacity, best cycling performance and best rate performance. The capacity of P2-LTO at 0.2C can reach 224.3 mAgh?1, which is much higher than the theoretical specific capacity of LTO (175 mAgh?1). The discharge capacity of P2-LTO in the first cycle at 10C is 178.9 mAgh?1. The results of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) show that the electrode polarisation and electrochemical impedance of P2-LTO were lower than that of pure LTO. Better capacity and rate performance can be obtained by adding PEG as a template agent to a LTO system. It is a simple and effective method to produce high-performance LTO anode materials. 相似文献
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Two non-flammable electrolytes 1 M LiPF6 in sulfolane (TMS) + 5 wt% VC and 0.7 M lithium bis(trifluoromethanesulphonyl)imide (LiNTf2) in N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulphonyl)imide (MePrPyrNTf2) + 10 wt% gamma-butyrolactone (GBL) were tested with Li4Ti5O12 (LTO) as highly promising anode material for application in lithium-ion batteries. The results were compared for the titanium anode in the classic electrolyte: 1 M LiPF6 in propylene carbonate + dimethyl carbonate (PC + DMC, 1:1). The performances of LTO/electrolyte/Li cell were tested using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge/discharge and scanning electron microscopy (SEM). SEM images of electrodes and those taken after electrochemical cycling showed changes which may be interpreted as a result of solid-state interface formation. Good charge/discharge capacities and low capacity loss at medium C rates preliminary cycling was obtained for the Li4Ti5O12 anode. For LTO/1 M LiPF6 in PC + DMC/Li system, the best capacity was obtained at C/10 and C/3 (145 and 154 mAh g?1, respectively). In the case of a system working on the basis of a TMS solution (1 M LiPF6 in TMS + 5 wt% VC) the best value was obtained at a C/5 current and an average of more than 150 mAh g?1 (86 % of theoretical capacity). For the 0.7 M LiNTf2 in MePrPyrNTf2 + 10 wt% GBL electrolyte, the highest capacitance value (at C/20 current) of about 150 mAh g?1 was observed. The 1 M LiPF6 in TMS + 5 wt% VC and 0.7 M LiNTf2 in MePrPyrNTf2 + 10 wt% GBL electrolytes had a relatively broad thermal stability range and no decomposition peak was observed below 150 °C. 相似文献
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《Ceramics International》2017,43(10):7600-7606
A nanocomposite of Li4Ti5O12 particles coated with polythiophene (PTh) was fabricated as advanced anode for rechargeable lithium-ion batteries. The conducting PTh layer was successfully coated on the surface of Li4Ti5O12 through the in-situ oxidative polymerization method. Benefiting from the core-shell structure, specific capacities as high as 171.5, 168.2 and 151.1 mA h g−1 at 0.2, 1 and 10 C are obtained in the Li4Ti5O12/PTh composite. The electrochemical results also show that the Li4Ti5O12/PTh exhibits remarkably improved cycling performance as compared with the Li4Ti5O12 anode. Moreover, the charge-transfer resistance of Li4Ti5O12/PTh electrode is much lower than that of the bare Li4Ti5O12, revealing that the PTh coating can significantly increase the electron conductivity between the Li4Ti5O12 particles. The excellent electrochemical performance of the as-fabricated Li4Ti5O12/PTh composite can be ascribed to the PTh layer which can suppress the dissolution of active material into the LiPF6 electrolyte and enhance the electron conductivity of Li4Ti5O12 nanocrystals. Thus, the Li4Ti5O12/PTh composite is an advanced anode for use in high performance lithium-ion batteries application. 相似文献
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提高钛酸锂负极材料倍率性能的研究进展 总被引:1,自引:0,他引:1
锂离子动力电池目前存在的主要问题为快速充电和安全性能较差。与石墨负极相比,钛酸锂负极能够明显提高锂离子动力电池的快速充电和安全性能,具有较大的应用前景。介绍了钛酸锂的嵌脱锂机制,分析了提高钛酸锂倍率充放电性能的主要方法,发现钛酸锂与金属和碳基材料复合,能够显著提高材料的电化学性能;通过控制钛酸锂形貌,也可得到倍率性能良好的钛酸锂,但是材料的振实密度较低;制备由纳米级一次粒子组成的微米级二次粒子,材料兼具纳米级一次粒子优越的电化学性能和微米级粒子较高的振实密度。总体而言,高性能钛酸锂材料的设计和制备已经取得了重大进展,然而目前钛酸锂电池面临的主要问题是其胀气行为,所以未来的研究重点将是揭示和研究钛酸锂电池的胀气机理和解决机制。 相似文献
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Xiaoyan Han Wenchao Tang Zonghui Yi Jutang Sun 《Journal of Applied Electrochemistry》2008,38(12):1671-1676
A rheological phase reaction method was introduced to synthesize LiNiVO4 powder material. The product was tested using XRD, SEM and electrochemical measurement methods. It was found that single
crystal grain LiNiVO4 is easily prepared with the rheological phase reaction; the intermediate product NiV(IV)O3 is the electrochemical active center; the product prepared at 700 °C for 18 h possess the best morphology of single crystal
body and exhibits excellent performance as anode material with a small capacity fade. This indicates that LiNiVO4 is a good anode material for lithium-ion batteries and the rheological phase reaction is a simple, economical and effective
method to synthesize a series of functional materials. 相似文献