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Synthesis and characterization of nano-scale vanadium oxides, vanadium phosphates as cathodes for lithium batteries.

机译：纳米级钒氧化物，磷酸钒钒作为锂电池正极的合成与表征。

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摘要

Progress in rechargeable lithium batteries for applications from small electronic devices to hybrid vehicles is intimately related to the successful research of advanced cathode materials. For improving the performance of lithium batteries, the search for cathode materials focuses on the investigation of insertion materials with a layered or open structure for reversible intercalation/deintercalation of lithium ions. Amongst insertion compounds, vanadium oxides and their derivatives with varied oxidation states (V5+, V4+ and V 3+) and desirable structures have attracted much attention. Onedimensional (1D) nanostructured building blocks such as nanorods, nanowires and nanoribbons, have attracted worldwide attention because of their distinctive geometries, outstanding physical and chemical properties and their potential applications in lithium batteries. Therefore, the investigation of nano-scale vanadium oxides with a layered structure is the subject of this thesis.;It was confirmed that the hydrothermal technique has advantages for the synthesis of vanadium oxides with layered structures. Here we present new methodology to control the morphology of vanadium oxides by using vanadium-polymer composite fibers, and form single-crystalline nanofibers with a layered structure through a hydrothermal treatment. By this synthesis method, two new layered vanadium oxides with dimensions ≤ 100 nm have been successfully obtained, vanadium oxide nanofibes (H0.48V4O10 · 2.0H2O) and lithium intercalated nanorods (Li 1.6H0.48V8O20 · 4.0H2O). The electrochemical performance of the nano-scale vanadium oxides as cathodes for lithium cells has been dramatically improved after the removal of interlayer water and hydronium ions. Additionally, the synthesis method has successfully produced nanoscale singlecrystalline VO2 (B) with an average width of 100 nm.;LiVPO4OH has been first synthesized hydrothermally by using vanadium pentoxide and lithium dihydrogen phosphate as starting materials. The pH value in the initial reaction solution plays an important role for the formation of lithium vanadium phosphate. The electrochemical behavior shows that the redox reaction of vanadium ions offers higher charge/discharge potentials in phosphates than in vanadium oxides, as expected for the inductive effect.
机译：从小型电子设备到混合动力汽车的可再充电锂电池的进步与先进正极材料的成功研究密切相关。为了提高锂电池的性能，寻找正极材料的重点在于对具有可逆嵌入/脱嵌锂离子的层状或开孔结构的插入材料的研究。在插入化合物中，具有变化的氧化态（V5 +，V4 +和V 3+）和所需结构的钒氧化物及其衍生物引起了人们的极大关注。一维（1D）纳米结构构件，例如纳米棒，纳米线和纳米带，因其独特的几何形状，出色的物理和化学特性以及在锂电池中的潜在应用而吸引了全世界的关注。因此，研究具有层状结构的纳米级钒氧化物是本课题的研究重点。证实了水热技术在合成具有层状结构的钒氧化物方面具有优势。在这里，我们提出了一种新的方法，通过使用钒聚合物复合纤维来控制钒氧化物的形态，并通过水热处理形成具有层状结构的单晶纳米纤维。通过这种合成方法，成功地获得了两种新的尺寸≤100 nm的层状钒氧化物，即钒氧化物纳米纤维（H0.48V4O10·2.0H2O）和锂插层纳米棒（Li 1.6H0.48V8O20·4.0H2O）。去除层间水和水合氢离子后，纳米级钒氧化物作为锂电池阴极的电化学性能得到了显着改善。此外，该合成方法成功地制备了平均宽度为100 nm的纳米级单晶VO2（B）。首先，以五氧化二钒和磷酸二氢锂为原料，水热合成了LiVPO4OH。初始反应溶液中的pH值对磷酸锂钒的形成起重要作用。电化学行为表明，钒离子的氧化还原反应在磷酸盐中提供的充电/放电电位比在钒氧化物中更高，这是感应效应所期望的。

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  • 作者

    Ban, Chunmei.;

  • 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.
  • 学位 Ph.D.
  • 年度 2008
  • 页码 194 p.
  • 总页数 194
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 无机化学;
  • 关键词

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