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Ti-based anode materials with the nominal compositions Li4Ti5CuxO12 + x (x = 0, 0.075, 0.15, 0.3, 0.6, 1.20 and 1.67) were synthesized at 800 °C by a solid-state reaction process. X-ray diffraction analysis indicated that the sintered samples were composed of intergrown spinel-type Li4Ti5O12 and Li2CuTi3O8, and a small amount of Li2O. Scanning electron microscopy, electrical resistance measurement and galvanostatic cell cycling were also employed to characterize the structure and properties of the double spinel samples. It is proposed that the first lithiation of the component Li2CuTi3O8 leads to the in situ production of Cu that can significantly improve the rate performance of Li4Ti5CuxO12 + x. The optimal nominal composition is Li4Ti5Cu0.15O12.15. 相似文献
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Highly lithium ion conductive composites with Al-doped Li7La3Zr2O12 (LLZ) and amorphous Li3BO3 were prepared from sol–gel derived precursor powders of LLZ and Li3BO3. Precursor LLZ powders with cubic phase were obtained by a heat treatment of the precursor dried gel at 600 °C. Pellets of the mixture of the obtained LLZ and Li3BO3 were first held at 700 °C, and then successively sintered at 900 °C. Density of the sintered pellet with Li3BO3 was larger than that of the pellet without Li3BO3. From the TEM observation, the pellets were found to consist of cubic LLZ and amorphous Li3BO3. Total electrical conductivity of the obtained LLZ–Li3BO3 composite was 1 × 10− 4 Scm− 1 at 30 °C. 相似文献
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以葡萄糖为碳源,采用固相法制备了Li4Ti5O12/C复合材料. 探讨了不同反应气氛(N2/O2)对材料物理性质及电化学性能的影响,并通过XRD、SEM、BET、电导率、电性能等测试手段对其进行了表征. 结果表明,N2气气氛中烧结的样品粒度、比表面积、电导率均比空气中烧结样品大. N2气中烧结样品的倍率性能优于空气中烧结样品,在以0.1 C倍率充放电时,首次放电比容量为166.8 mA·h/g. 2种样品在1 C时,经过50次循环容量保持率差别不大. 相似文献
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自Sony公司推出锂离子二次电池以来,以AC/LiCoO2体系为主的商品锂离子电池由于具有高容量、高电压、环境友好等优势,已在便携式电子设备领域得到了广泛应用。但由于C/LiCoO2体系的锂离子电池存在成本、安全和寿命等方面的问题,限制了其在动力和储能领域的应用。选择合适的锂离子电池材料,开发新的电池体系是解决问题的关键。 相似文献
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Caixia Qiu Zhongzhi Yuan Ling Liu Neng Ye Jincheng Liu 《Journal of Solid State Electrochemistry》2013,17(3):841-847
A sol–gel method using Ti(OC4H9)4, LiCH3COO·2H2O, and La(NO3)3·6H2O as starting materials and ethyl acetoacetate as chelating agent to prepare pure and lanthanum (La)-doped Li4Ti5O12 is reported. The structure and morphology of the active materials characterized by powder X-ray diffraction and scanning electron microscopy analysis indicate that doping with a certain amount of La3+ does not affect the structure of Li4Ti5O12, but can restrain the agglomeration of the particles during heat treatment. The electrochemical properties measured by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge cycling tests show that La-doped Li4Ti5O12 presents a much improved electrochemical performance due to a decrease in charge transfer resistance. At current densities of 1 and 5 C, the La-doped Li4Ti5O12 exhibits excellent reversible capacities of 156.16 and 150.79 mAh?g?1, respectively. The excellent rate capability and good cycling performance make La-doped Li4Ti5O12 a promising anode material for lithium-ion batteries in energy storage systems. 相似文献
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《Comptes Rendus de l''Academie des Sciences Series IIB Mechanics Physics Astronomy》2001,4(11):845-848
7Li nuclear magnetic resonance relaxation times, T1 and T1ρ, versus temperature are reported in the 150–900 K temperature range on the lithium lanthanum titanates, Li3xLa2/3–x□1/3–2xTiO3, which are fast ionic conductors. Two characteristic frequencies of Li+ motions are evidenced in these compounds: the first is in the range of the Larmor frequency when the second one is in the range of the radio-frequency field. These frequencies are respectively attributed to motion of the Li+ ion inside the cage formed by the oxygen ions and to jumps between the cages. The T1 and T1ρ studies on 6Li nuclei confirm the above results and show that the relaxation is not due to quadrupolar interaction at a variance, which is generally accepted. 相似文献
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以葡萄糖为碳源,采用固相法制备了Li4Ti5O12/C复合材料。探讨了不同反应气氛(N2/O2)对材料物理性质及电化学性能的影响,并通过XRD、BET、电导率、电性能等测试手段对其进行表征。结果表明:氮气气氛中烧结的样品粒度、比表面积、电导率均比空气中烧结样品大。氮气中烧结样品的倍率性能优于空气中 烧结样品,在以0.1C倍率充放电时,首次放电比容量为166.8mAh/g。两样品1C时,经过50次循环容量保持率差别不大。 相似文献
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Liang An Meng Yuan Wang Tao Xiong Chao Yan Zhaoxiong Xu Zhihua 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2020,94(5):1067-1072
Russian Journal of Physical Chemistry A - A new magnetic Ag3PO4–TiO2–Fe2O3 photocatalyst (Ag–Ti–Fe) has been synthesized by a solid-state blending method. The sample was... 相似文献
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将LiNO3和Ti(OC4H9)4填填充在有序介孔碳CMK-3 孔道中, 然后烧结合成了Li4Ti5O12/CMK-3复合材料. 利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线衍射(XRD)对其结构和微观形貌进行了表征. 利用差热-热重分析(TG-DTA)测试复合材料中Li4Ti5O12的含量. 利用充放电测试、循环伏安和电化学阻抗技术考察了复合材料作为锂离子电池负极材料的性能. 发现Li4Ti5O12分布在CMK-3孔道中及其周围, 复合材料的高倍率充放电性能显著优于商品Li4Ti5O12, 复合材料中Li4Ti5O12的比容量明显高于除去CMK-3的样品(在1C倍率时比容量为117.8 mAh·g-1), 其0.5C、1C和5C倍率的放电比容量分别为160、143 和131 mAh·g-1, 库仑效率接近100%, 5C倍率时循环100次的容量损失率只有0.62%. 本研究结果表明CMK-3明显提高了Li4Ti5O12的高倍率充放电性能, 可能是CMK-3特殊的孔道结构和良好的导电性减小了Li4Ti5O12的粒径并提高了其电导率. 相似文献
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由于电子和信息行业的需要, 过去十年锂离子电池得以快速发展. 目前, 锂离子电池仍呈现需求量增长的趋势, 对锂离子电池的安全性要求也越来越高. 因此促使寻找一种比碳/石墨材料更安全, 循环性能更理想的锂离子电池负极材料以满足电动汽车等新兴行业的需求. 尖晶石型Li4Ti5O12作为“零应变材料”具有优异的循环稳定性、价格便宜、容易制备、较高的平台电压和良好的安全性, 已成为锂离子动力电池负极材料的研究热点, 被认为是目前最具应用前景的锂离子电池负极材料. 由于形貌选择对于Li4Ti5O12材料的电化学性能有着至关重要的影响, 本文综述了球形、多孔(中空)结构、纳微结构、核壳结构等不同形貌Li4Ti5O12的合成及其性能研究的最新进展; 总结了各种形貌的优点, 已解决和待解决的问题, 常用合成方法以及各自的适应领域; 并对Li4Ti5O12材料的发展趋势进行了展望. 相似文献
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A carbon-free Li(4)Ti(5)O(12) electrode has shown excellent electrochemical performance without any effort to enhance the electrical conductivity. Partial reduction of Ti(4+) and a metallic Li(7)Ti(5)O(12) phase are suggested to be possible origins of the exceptional behavior. 相似文献