【作者】 张忠东；

【导师】 赵立竹；

【作者基本信息】 东北师范大学 ， 凝聚态物理， 2009， 硕士

【摘要】 随着信息技术的发展,人们对便携式电子产品的需求日益提高。锂离子电池因其具有比容量高、功率大、寿命长、无记忆效应,以及性价比高等优点,成为便携式电子产品可充式电源的主要选择。目前商用锂离子电池正极材料主要是电化学性能非常稳定的LiCoO2,然而,由于钴的资源匮乏导致价格昂贵,并且钴有剧毒,因此研究者一直在寻找其理想的替代材料。锰的资源丰富且毒性小,因而人们希望用锰替代钴,LiMnO2作为锂离子电池正极材料的研究越来越广泛,该材料在比容量以及循环寿命方面仍存在大量有待进一步提高的问题,如何制备得到高比容量且循环性能稳定的LiMnO2正极材料是近年来研究关注的热点。本文从锂离子电池的发展历程开始,对锂离子电池的工作原理、正极材料层状LiMnO2的结构及电化学性质、制备方法与掺杂改性等方面进行了综述,经分析和比较,提出了今后正极材料研究和应用的发展方向。LMinO2实际是一个同质多晶化合物,有正交和单斜及六方3种晶系,分别具有Pmnm、C2/m和R3 m空间群结构。理论研究表明六方结构( R3 m)的LMinO2很难合成,在热力学平衡条件下,由于Mn3+之间的反铁磁相互作用,正交LiMnO2比单斜LiMnO2稳定。但两者在化学反应或电化学反应中容易转变为类尖晶石结构。正交LiMnO2(o-LiMnO2)与单斜LiMnO2(m-LiMnO2)一样具有285 mA·h/g的理论容量,与m-LiMnO2相比,o-LiMnO2更容易合成,电化学稳定性更好。国内外对锂离子电池正极材料的层状LiMnO2的制备方法及电化学性能进行了广泛研究,提出了多种制备方法,较普遍使用的有高温固相反应法、离子交换法和水热合成法等。研究表明,掺杂有利于提高LiMnO2的电化学性能,抑制了材料的结构向尖晶石结构的进一步转变。通过对大量文献的分析研究,提出制备电化学性能优异的锂离子电池正极材料层状LiMnO2有意义的建议,对LiMnO2材料深入细致的研究直至走向应用,具有重要的参考价值。更多还原

【Abstract】 With the development of electronic information technology,demands for portable electronic devices increase.Li-ion battery becomes main choice for Battery charging power source of the carriable electronic product.LiCoO2 has become the main cathode material in commercial lithium-ion batteries.Because of the high cost and toxicity of LiCoO2,researchers have been searching for alternative materials.They wish that the manganese can alternate the cobalt because of Abound in natural resources and innoxious,so LiMnO2 as Li-ion battery cathode material is paied close attention by much more researchers,there are great quantities spend for improving further problems.It is focus of attention to manufacture LiMnO2 with high specific capacity and steady cyclicity.I summarize the structure,principle of work,electrochemistry performance,preparation method and the multi-substitution at the beginning of development of battery .I put forward a developing direction of study and application of cathode material in future.LiMnO2 is a kinds of homogeneous polycrystal compound,it contains orthogonality system,monoclinic system and hexagonal system,with space group Pmnm、C2/m and R3 m.The theory study shows that the LiMnO2 with space group R3 m is very difficult to be synthesized . Under thethermodynamics balance condition ,orthogonality system LiMnO2 is more steady than monoclinic system LiMnO2 because of counter-ferromagnetic coactions among Mn3+,but they all become spinel structure easily in electrochemical reaction. o-LiMnO2 and m-LiMnO2 have the same theory capacity 285 mA·h/g ,compare with m-LiMnO2, o-LiMnO2 is synthesized easily and has better electrochemical stability.People have done lots of study on Preparation method and electrochemistry function about LiMnO2,the commonsense method is high temperature solid reaction process,ion exchange technique andhydrothermal synthesis method.The study indicates that multi-substitution is propitious to improve electrochemical stability of LiMnO2 and to keep down turning to spinel structure.It is important reference value to further study on LiMnO2 material ,we give some useful advice on preparation of Li-ion battery cathode material stratified.更多还原