【作者】 李胜军；

【导师】 陈猛；

【作者基本信息】 哈尔滨工程大学 ， 应用化学， 2004， 硕士

【摘要】 锂离子电池是一种新型二次电池，在二十世纪90年代初，由日本SONY公司率先研制成功，并推向市场。锂离子电池具有工作电压高、比能量高、循环寿命长、安全性能好以及使用温度范围宽等特点。在锂离子电池众多的正极活性材料中，尖晶石型LiMn₂O₄化合物，由干其原材料资源丰富，价格低，环境污染小，合成工艺简单，成为最有希望取代LiCoO₂的材料。本文对小批量制备尖晶石型LiMn₂O₄材料的工艺条件进行了研究，主要包括原材料选择、原材料配比、烧结温度和烧结时间4个方面，通过对以上4个因素的考察，对LiMn₂O₄材料的生产工艺过程进行优化，为LiMn₂O₄材料的工业化生产提供科学依据。同时，通过金属离子掺杂对LiMn₂O₄材料进行改性，提高材料的电化学性能，所选用的金属掺杂离子为Ni²⁺、Mg²⁺和Co³⁺。XRD测试结果表明对LiMn₂O₄材料进行金属离子掺杂后，所得到的材料都基本呈现尖晶石结构。材料的电化学性能测试在方型实体电池中完成，负极采用中间相碳微球（MCMB），电解液采用1MLiPF₆—EC+DEC+EMC，隔膜为celgard2400。通过测试发现金属离子掺杂提高了材料的循环性能，尤其是高温循环性能，LiNi_0.1Mn_1.9O₄与LiMn₂O₄材料相比，在55℃下循环过程中的容量损失减小了近50％。以LiOH、电解MnO₂和Co（CH₃COO）₂为原料，在800℃烧结温度下得到的LiCo₉0.08)Mn_1.92O₄材料实际比容量达到78mA／g左右。由LiCo_0.08Mn_1.92O₄材料得到的实验电池在常温1C下，经过1000次，电池的容量保持率在85％以上。LiCo_0.08Mn_1.92O₄材料大功率放电性能良好，4C时的放电容量为0.1C时放电容量的85％，此倍率下的比功率和比能量约为520W／kg和60Wh／kg。此材料的月自放电率在6％以下。可以看出。LiCo_0.08Mn_1.92O₄材料是一种极有希望的锂离子电池正极材料。更多还原

【Abstract】 Lithium ion battery is a new type of rechargeable battery. In the beginning of 1990s, SONY coporation declared that they found a practicable battery system which used carbon and lithium cobalt oxide as negative material and positive material respectively. This kind of battery was brought to the market soon after that declaration. Lithium ion batteries have many advantages, such as high voltage, high specific energy, long cycle life, reliable performance and wide range of working temperature. Among the various kinds of cathode material, spinel lithium manganese oxide LiMn2O4 was believed to be the most promising one because of its abundant resources, low cost, little pollution and simple synthesis process.In this thesis, the spinel LiMn2O4 was synthesized in serial production by solid-state reaction and the electrochemical properties was tested in rectangular lithium ion battery with microcarbon Microbead(MCMB) as anode material and 1 M LiPF6 desolved in the mixture of ethylene carbonate(EC) , dimethyl carbonate(DMC) and ethylene methyl carbonate(EMC) as the electrolyte. To optimize the synthetic process, we investigated the effect of four factors: different row material, the ratio of lithium and manganese, calcination temperature and calcinations time on the properties of the production. The production which was fabricated from LiOH or LiNO3, instead of Li2CO3, displays significant advantages. Optimum results were a reaction time about 75h and a calcinations temperature about 800.On the other hand, we studied the influence of doped-cations, such as Ni2+, Mg2+ and Co3+. The structure of the doped spinel LiMn2O4 was proved to be pure spinel through X-ray diffraction measurements. The cycle life was improved by doped-cations. The properties of LiCoo.ogMn1.92O4 were studied especially which initial capacity is about 78mAh/g and 85percent is remained after 1000 cycles. The attractive advantage is that LiCoo.o8Mn1.92O4 can work at high discharge rates. The discharge capacity at 4C is about 85percent of the capacity at 0.1C . The specific energy and power at 4C is about 60Wh/kg and 520W/kg. The self-discharge rate isis below 6 percent per month. So LiCoo.o8Mn1.92O4 is a promising cathode material which can be put into use.更多还原