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锂离子电池正极材料LiMO2(M=Ni,Co,Mn)的合成与表征

Synthesis and Characterization of LiMO2(M=Ni,Co,Mn) Cathode Materials for Lithium Ion Battery

【作者】 蒋丹丹

【导师】 袁宏明;

【作者基本信息】 吉林大学 , 无机化学, 2012, 硕士

【摘要】 本论文主要采用了水热法和固相法相结合的合成路线,制备了Li-Ni-Co-O2层状化物和Li-Ni-Mn-Co-O2层状化合物,分别对这两个系列的化合物进行了结构表征和电学性能测试。第一章,对锂离子电池的工作原理进行了说明,详细的介绍了常见的几种锂离子电池正极材料的优缺点及其合成方法。对研究背景和实验目的进行了阐述。第二章,对锂离子电池正极材料常见的合成方法做了比较详尽的说明,介绍了论文中使用的实验试剂、设备及测试手段。并且对纽扣电池正极片的制作和手套箱中纽扣电池的制作流程做了十分详细的阐述。第三章,成功的合成了LiNi0.5Co0.5O2和LiNi0.6Co0.4O2正极材料,通过XRD、XPS、SEM、恒流充放电测试等手段,进行了结构表征和电化学性能测试。我们的样品具有良好的物理特性和电化学性能。第四章,将锰、镍、钴源化合物与氢氧化锂水溶液进行水热反应,得到前驱体;前驱体经过800℃焙烧10h后得到Li(Ni1/3Mn1/3Co1/3)O2和LiNi(0.4)Mn(0.4)Co(0.2)O2化合物。我们对目标产物进行了一系列分析。证实了论文中使用制备方法具有一定实际的意义。通过改良合成方法,可以改善材料物理特性和电化学性质。

【Abstract】 In the revolution of energy, LIB (lithium ion battery) holds an important position byits advantages. It has gotten the rapid development and wide application in theproduction and life of the human. Now LIB has penetrated into every field of our life,such as electronic products: mobile phone, computer, MP3, MP4etc. In terms oftransportation, application of lithium-ion battery is not to be underestimated.. Nowmany countries pay more attention to research and development of EV (electricvehicles) and HEV (hybrids electric vehicles), developed countries spend hugeamounts of money to support and promote the development of EV. In France, theUnited States, Japan, the EV enterprises have been successfully listed. In Paris and LaRochelle, EV charging station networks have been built. Although starting lately inChina, the EV research has become the focal supporting project. In space, the batteryusing in the spacecraft is solar battery, so it has certain limitation, it can’t workproperly when sunless. At this time, energy storage equipment with high reliability, Inthe low temperature with good performance, long cycle life, higher energy density isneeded. LIB occurs in not only national defense communications but alsosophisticated weapons. In the energy storage, LIB moreover becomes the first choice.Cathode materials as important component for LIB have become the focus ofresearch. In recent years, mixed transition metal layered compound,has attracted moreattention. Li NixCo1-xO2material has high specific capacity, good cycle performance, low cost but poor thermal stability. Li-Ni-Co-Mn-O2material is the complex ofLiCoO2, LiNiO2and LiMnO2, it inherited the advantages of three kinds of ions andinhibit defects greatly. However, the morphology of its homologue is difficult tocontrol. Some products with non stoichiometric ratio don’t meet the usingrequirements. The prepared material using low temperature technology for example,sol-gel method, combustion method and co-precipitation method own more excellentcycle performance. Liquid phase synthesis makes ionic mix more fully and reactionactivity increase, it is helpful to get the pure phase of the product. In addition, themethod uses the lower calcining temperature, so that the product has smaller particle,higher specific surface and better crystal lattice strain.This paper mainly uses the synthesis route combining the hydrothermal method andsolid phase method to prepare the layered compounds of Li-Ni-Co-O2andLi-Ni-Mn-Co-O2, and do the structure characterization and electrochemical propertiestest for the two series of compounds separately.1, we prepare the compounds of LiNi0.5Co0.5O2and LiNi0.6Co0.4O2by thehydrothermal method and high temperature calcination method. The sample structure,valence state and morphology are characterized. The compounds have relativelyuniform particle size, good dispersion and good layered structure, the valences of Niand Co element are+3valence. In the constant current charge and discharge test, theinitial capacity of our sample is very close to the theoretical capacity. The capacityretention reached86%, this also illustrates our sample has excellent electrochemicalperformance.2, The manganese source compounds, the nickel source compounds and cobaltsource compound lithium and lithium hydroxide aqueous solution are mixed andconduct hydrothermal reaction to get manganese, cobalt, nickel oxide precursor; thenget Li(Ni1/3Mn1/3Co1/3)O2and LiNi0.4Mn0.4Co0.2O2compounds after the precursor800℃baking10h. We do a series analysis on the target products. Based on theelectrochemical performance test of the sample, sample capacity is relatively high at acurrent density of20mA/g, voltage within2.5-4.4v. After50charge-discharge cycles,the capacity retention is above160mAh/g. Li(Ni1/3Mn1/3Co1/3)O2has good electrochemical reversibility and structural stability. At the same time, samples haverelatively stable voltage platform.

  • 【网络出版投稿人】 吉林大学
  • 【网络出版年期】2012年 12期
  • 【分类号】TM912
  • 【下载频次】247
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