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首页> 外文学位 >Synthesis of some vanadium oxides and layered lithium nickel(1-y-z)manganese(y)cobalt(z)oxide compounds and their properties as cathodes for lithium-ion batteries.
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Synthesis of some vanadium oxides and layered lithium nickel(1-y-z)manganese(y)cobalt(z)oxide compounds and their properties as cathodes for lithium-ion batteries.

机译：某些钒氧化物和层状锂镍（1-y-z）锰（y）钴（z）氧化物的合成及其作为锂离子电池正极的性能。

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摘要

One of the motivations for the work reported in this Dissertation is derived from the need to replace the commercial cathode material lithium cobalt oxide, LiCoO2, which is found in the SONY lithium rechargeable batteries. The cathode LiCoO2 is expensive and gives a low energy density and is thus suitable only for low scale application such as in cellular phones, laptops and other microelectronics.; Some vanadium oxides and mixed metal manganese oxides LiNi1-y-z MnyCozO2 were studied due to their relatively lower cost. The vanadium oxides were hydrothermally synthesized, whereas the compounds LiNi1-y-zMnyCo zO2 were synthesized by the high temperature solid-state reaction method. The compounds were characterized and tested as cathodes.; Two categories of novel vanadium compounds were synthesized; the hollandite and the double-layered types of vanadium oxides. These compounds were fully characterized. The hollandite type consists of tunnel structures, whereas the other type consists of double sheets of vanadium oxide. These interesting structures could find use in catalytic processes and in ion-exchanging reactions among other uses. Both types demonstrated a high discharge capacity in lithium cells, and hence high energy density as well as high rechargeability. However, their capacity retention was low.; Results of two studies on the layered LiNi1-y-zMn yCozO2 are reported. Each transition metal ion in the compounds was found to play a key role in their electrochemical performance. The temperature of their synthesis was also found to affect their electrochemical properties. The nickel was thought to be critical in converting the manganese to be more cobalt-like in its redox properties hence widening the working potential window of the Mn. However, it was found that the Mn was electrochemically inert with all the redox activity residing on the nickel. The cobalt is useful in stabilizing the layered structure.; Among the studied compositions, the compound LiNi0.4Mn 0.4Co0.2O2 was found to have the highest reversible capacity. It also demonstrates a remarkable rate capability hence power density, since it operates with a high current density of 2.0 mA/cm2 reversibly, while it gives a high capacity retention of about 70%.
机译：本论文报道的工作动机之一是由于需要更换商用正极材料钴酸锂LiCoO2，而这种材料已在SONY锂可充电电池中找到。阴极LiCoO2价格昂贵且能量密度低，因此仅适用于小规模应用，例如手机，笔记本电脑和其他微电子产品。研究了一些钒氧化物和混合金属锰氧化物LiNi1-y-z MnyCozO2，因为它们的成本相对较低。钒氧化物是水热合成的，而化合物LiNi1-y-zMnyCo zO2是通过高温固态反应方法合成的。将该化合物表征并测试为阴极。合成了两类新型钒化合物：钙铁矿和双层类型的钒氧化物。这些化合物已得到充分表征。钙铁矿类型由隧道结构组成，而另一种类型由双层钒氧化物组成。这些有趣的结构可用于催化过程和离子交换反应以及其他用途。两种类型在锂电池中均显示出高放电容量，因此具有高能量密度以及高充电性。但是，它们的容量保持率很低。报道了关于层状LiNi1-y-zMn yCozO2的两项研究的结果。发现化合物中的每种过渡金属离子在其电化学性能中起关键作用。还发现它们的合成温度影响它们的电化学性能。镍被认为对于将锰的氧化还原性能转变为更像钴一样至关重要，因此扩大了锰的工作电位范围。然而，发现Mn是电化学惰性的，所有的氧化还原活性都存在于镍上。钴可用于稳定层状结构。在研究的组合物中，发现化合物LiNi0.4Mn 0.4Co0.2O2具有最高的可逆容量。它还具有出色的速率能力和功率密度，因为它可逆地以2.0 mA / cm2的高电流密度工作，同时具有约70％的高容量保持率。

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  • 作者

    Ngala, J. Katana.;

  • 作者单位

    State University of New York at Binghamton.;

  • 授予单位 State University of New York at Binghamton.;
  • 学科 Chemistry Inorganic.; Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2004
  • 页码 165 p.
  • 总页数 165
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 无机化学;工程材料学;
  • 关键词

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