锂离子电池钛酸盐负极材料的制备及性能研究

发布时间：2018-07-05 15:53

本文选题：锂离子电池 + 钛酸盐负极　；参考：《新疆师范大学》2015年硕士论文

【摘要】：尖晶石结构Li Cr Ti O4、Li Fe Ti O4、Li2Zn Ti3O8、Li2Mg Ti3O8负极材料具有结构稳定,成本低,环境友好,电化学性能优异等优点。是一类很有发展潜力的锂离子电池负极材料。通过如XRD、SEM、TEM、CV和充放电测试等多种表征手段,系统的研究了合成温度和时间对钛酸盐负极材料电化学性能的影响以及新型钛酸盐负极材料的电化学机理。1.本文采用高温固相法合成了Li Cr Ti O4负极材料,结果表明,Li Cr Ti O4材料在电化学循环过程中结构稳定。800℃-12h合成的样品具有良好的循环稳定性和优异的倍率性能。在电流密度为0.5C,1C,2C和5C时材料的放电容量分别为158m Ah?g-1,146m Ah?g-1,140m Ah?g-1和126m Ah?g-1。2将800℃-12h合成Li Cr Ti O4作为负极材料,Li Fe PO4/C作为正极材料组装成Li Fe PO4/Li Cr Ti O4全电池。结果表明Li Fe PO4/Li Cr Ti O4全电池具有优异的倍率性能和可逆性能。Li Fe PO4/Li Cr Ti O4全电池具有稳定的充放电平台~1.8V,在0.2C倍率下材料的放电容量为116.8m Ah?g-1,循环100周后保持在110.5m Ah?g-1。容量保持率为95%。3.采用高温固相法700℃-8h合成了碳包覆尖晶石结构Li Fe Ti O4材料。结果表明,碳包覆有助于提高材料的导电性,有利于锂离子在Li Fe Ti O4材料中的嵌入和脱出。因此,尖晶石结构Li Fe Ti O4/C材料的电化学性能优于Li Fe Ti O4材料。电流密度为0.5C时,Li Fe Ti O4/C材料的首周放电容量达327.8m Ah?g-1,循环50周后稳定在308.3m Ah?g-1。在5C时保持了205m Ah?g-1放电容量。表明材料具有良好的倍率性能。4.采用高温固相法合成了Li2MTi3O8(M=Mg,Zn)材料。研究表明,尖晶石结构Li2MTi3O8(M=Mg,Zn)材料具有相似的晶体结构和相似的电化学机理,表现出相似的充放电平台,Li2MTi3O8(M=Mg,Zn)材料结构稳定电化学性能测试中具有优异的循环稳定性和良好的库伦效率,Li2Zn Ti3O8材料比Li2Mg Ti3O8材料具有更加优异的电化学性能。在室温下,充放电倍率为0.5C时,Li2Zn Ti3O8首次放电容量为225.5m Ah?g-1,100周循环后保持在250m Ah?g-1。Li2Mg Ti3O8首次放电容量为215.6m Ah?g-1,100周循环后保持在225m Ah?g-1。
[Abstract]:The spinel structure Li Cr Ti O4, Li Fe Ti O4, Li2Zn Ti3O8, Li2Mg Ti3O8 anode materials have the advantages of stable structure, low cost, friendly environment and excellent electrochemical performance. It is a kind of potential anode material for lithium ion batteries. The effect of time and time on the electrochemical properties of titanate anode materials and the electrochemical mechanism of new titanate anode materials.1., Li Cr Ti O4 negative electrode was synthesized by high temperature solid phase method. The results showed that the samples of Li Cr Ti O4 materials in the electrochemical cycle process were stable and stable at.800 C -12h synthesis. Excellent multiplier performance. The discharge capacity of the material at the current density of 0.5C, 1C, 2C and 5C is 158m Ah? G-1146m Ah? G-1140m Ah? G-1 and 126m? The.Li Fe PO4/Li Cr Ti O4 full battery has a stable charging and discharging platform ~1.8V. The discharge capacity of the material is 116.8m Ah? G-1 at the 0.2C ratio. After 100 weeks, the capacity retention of the material is maintained at the capacity of high temperature solid method at 700. The results show that carbon coating helps to improve the conductivity of the material and is beneficial to the insertion and removal of lithium ion in the Li Fe Ti O4 material. Therefore, the electrochemical performance of the spinel structure Li Fe Ti O4/C material is superior to the Li Fe Ti O4 material. The discharge capacity of 205m Ah? G-1 is maintained at the time of 308.3m Ah? G-1. at 5C. It shows that the material has good multiplier performance,.4. using high temperature solid-phase method to synthesize Li2MTi3O8 (M=Mg, Zn) materials. The platform, Li2MTi3O8 (M=Mg, Zn) material has excellent cyclic stability and good Kulun efficiency. Li2Zn Ti3O8 material has more excellent electrochemical performance than Li2Mg Ti3O8. At room temperature, when the charge discharge ratio is 0.5C, the initial discharge capacity of Li2Zn Ti3O8 is 225.5m Ah. The first discharge capacity held at 250m Ah? G-1.Li2Mg Ti3O8 is 215.6m Ah? G-1100 cycle after maintaining 225m Ah? G-1..
【学位授予单位】：新疆师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM912

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