高比能锂离子电池富锂材料合成与应用
发布时间：2018-07-14 15:03
【摘要】：因具有较高的工作电压、能量密度、长寿命和对环境友好等特点，锂离子电池已经成为新一代电动汽车、电动工具及电子产品的动力电源，已经广泛应用于能源、交通、通讯等不同的领域之中。目前，新一代高比能正极材料的开发已经成为锂离子电池的一个研究热点。富锂锰基正极材料因为具有高比能量，低成本等优点，被认为下一代高比能锂离子电池的正极材料候选材料之一。然而，这种材料存在电子导电性能较差、首次效率较低、循环性能较差等问题，并且材料在实际电池中的电化学性能研究较少，在一定程度上限制了该材料的商业化应用。本论文不但在实验室中进行了材料合成与材料改性研究，，以求提高该材料的电化学性能，还使用该材料进行了实效电池的制作和性能测试，取得了实效电池性能的第一手数据，为该材料的产业化提供了基础数据。 首先，利用共沉淀法合成了性能优异的前驱体材料Ni0.21Co0.12Mn0.67CO3，且通过对材料烧结温度、配锂量的优化，合成了一种性能较优的富锂锰基正极材料Li[Li0.17Ni0.17Co0.10Mn0.56]O2，由前驱体和碳酸锂混合均匀后在850℃下烧结得到，材料结晶性能较好、颗粒的大小适中，材料在充放电过程中形成的SEI膜的阻抗较小。材料电化学性能表明材料具有较低的首次不可逆容量，良好的循环性能：在2.0~4.6V0.05C电流下，50次循环后容量保持率为88%，首次充、放电比容量分别为298.1mAh g-1和256.1. mAh g-1。其次，富锂锰基正极材料Li[Li0.17Ni0.17Co0.10Mn0.56]O2表面的包覆改性：对该材料包覆具有电化学活性的LiCoPO4。包覆后循环性能得到了提升，并且我们对性能改善的原因进行了机理方面的初步探索LiCoPO4结构较稳定，能承受较高的充电电压，材料表面包覆LiCoPO4后，表面的LiCoPO4隔绝了富锂锰基正极材料与电解液的直接接触，能够有效阻止材料与电解液的反应，从而改善了材料电化学性能；最后通过实效电池制作，发现电池在循环中有气体产生，并证明该材料在实效电池中会析出氧气，通过实效电池电化学性能研究，发现该材料用于实效电池正极材料仍有待进一步研究。
[Abstract]:Because of its high working voltage, energy density, long life and environmental friendliness, lithium-ion battery has become a new generation power supply for electric vehicles, electric tools and electronic products, and has been widely used in energy and transportation. In different fields, such as communications. At present, the development of a new generation of high specific energy cathode materials has become a research hotspot in lithium ion batteries. Lithium-rich manganese based cathode materials are considered as candidates for the next generation of high specific energy lithium-ion batteries because of their advantages of high specific energy and low cost. However, this kind of material has some problems, such as poor electronic conductivity, low initial efficiency and poor cycling performance, and the electrochemical performance of the material in the actual battery is less, which limits the commercial application of the material to some extent. In this paper, not only the material synthesis and material modification were studied in order to improve the electrochemical performance of the material, but also the actual battery was made and the performance test was carried out, and the firsthand data of the actual battery performance was obtained. It provides the basic data for the industrialization of the material. Firstly, Ni _ (0.21) Co _ (0.12) mn _ (0.67) CO _ 3 precursor with excellent properties was synthesized by coprecipitation method. Li [Li 0.17Ni0.17Co0.10Mn0.56] O _ 2, a Li-rich manganese-rich cathode material, was synthesized and sintered at 850 鈩
本文编号：2122025
[Abstract]:Because of its high working voltage, energy density, long life and environmental friendliness, lithium-ion battery has become a new generation power supply for electric vehicles, electric tools and electronic products, and has been widely used in energy and transportation. In different fields, such as communications. At present, the development of a new generation of high specific energy cathode materials has become a research hotspot in lithium ion batteries. Lithium-rich manganese based cathode materials are considered as candidates for the next generation of high specific energy lithium-ion batteries because of their advantages of high specific energy and low cost. However, this kind of material has some problems, such as poor electronic conductivity, low initial efficiency and poor cycling performance, and the electrochemical performance of the material in the actual battery is less, which limits the commercial application of the material to some extent. In this paper, not only the material synthesis and material modification were studied in order to improve the electrochemical performance of the material, but also the actual battery was made and the performance test was carried out, and the firsthand data of the actual battery performance was obtained. It provides the basic data for the industrialization of the material. Firstly, Ni _ (0.21) Co _ (0.12) mn _ (0.67) CO _ 3 precursor with excellent properties was synthesized by coprecipitation method. Li [Li 0.17Ni0.17Co0.10Mn0.56] O _ 2, a Li-rich manganese-rich cathode material, was synthesized and sintered at 850 鈩
本文编号：2122025
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