稻壳制备锂离子电池炭负极材料的研究

【作者】 郝婕；

【导师】 王荣顺；

【作者基本信息】 东北师范大学 ， 物理化学， 2004， 硕士

【摘要】 锂离子电池具有工作电压高、循环寿命长、能量密度大、自放电低、“绿色”环保等优点，成为电池工业的研究热点。本论文详细介绍了锂离子电池发展及炭材料的研究进展，阐述了各种炭负极材料的结构和性能，介绍了锂嵌入反应机理。 本文选用农业副产品稻壳作为原材料制备锂离子电池负极材料，研究该材料的微观结构与电化学性能的关系。通过元素分析、XRD、Raman 光谱、BET 及 SEM 和电化学等测试手段对所得稻壳炭材料进行结构表征和性能测试。确定了稻壳制备锂离子电池炭材料的最佳实验条件。 所得结论如下： 1. 根据稻壳的热失重分析，确定稻壳的热处理过程为阶段式升 温过程； 2. 考察了不同的升温速率（0.5、2.5、5.0、10 ℃/min）对稻壳 炭材料结构与性能的影响。结果表明：所得炭材料为无定形 炭，以 5.0 ℃/min 的升温速率热解稻壳炭材料 H 含量和 H/C 比较高，电化学性能最好； 3. 考察了不同的炭化温度（500、600、700、800 ℃）对稻壳炭 材料结构与性能的影响。结果表明：随着炭化温度的升高， 稻壳炭材料的有序化程度增大，在炭化温度为 700 ℃时，材 料的比表面积较大，充放电性能最佳； 4. NaOH 能除去稻壳炭材料中存在的大量的硅的氧化物，因此考 察不同浓度 NaOH 溶液（0.1、0.5、1.0、2.0 、3.0、4.0、10 mol/L） 对稻壳炭材料结构与性能的影响。结果表明：稻壳炭材料经 NaOH 溶液处理后，显著提高了其中的含 C 量，（100）衍射 - I -<WP=5>东北师范大学硕士学位论文 作者：郝婕 峰 逐 渐 出 现 ， 充 电 容 量 基 本 上 呈 现 增 加 的 趋 势 ， 以 2.0mol/LNaOH 处理的稻壳炭材料的首次充放电容量和循环性 能最好；5. 在最佳实验条件下（炭化升温速率为 5.0 ℃/min、炭化温度为 700 ℃、处理稻壳所用 NaOH 的浓度为 2.0 mol/L），材料的首 次充电容量为 678.0 mAh/g，首次放电容量为 239 mAh/g，十 次循环后的放电容量为 161.9 mAh/g，充电容量为 155.2 mAh/g，充放电效率由首次的 35.2 %提高到 98.6 %。更多还原

【Abstract】 Rechargeable lithium ion batteries have a great prospect in electricindustries because of high voltage, high energy density, long cycle life, lowself-discharge ratio and goodness to environment. The development oflithium ion batteries and carbon anode materials are reviewed in detail. Thestructures and performances of carbon materials are studied, and themechanism of Li-ion inserting process is investigated. The anode carbon materials are prepared from rice husks (RH). Therelation between the electrochemical performance and the microcosmicstructure as anode materials is investigated. Rice husks are surveyed by thetemperature gravitation analysis (TGA), X-ray diffraction (XRD), Ramanspectrum, BET, SEM and its electrochemical property is characterized.Based on the results, the process of the raising temperature and experimentcondition are designed. Conclusions: 1. We determine the heat-treated process is phased according to the TGA. 2. The effect of different heat-treated rate on the microstructure and electrochemical performances is investigated. The results demonstrate that carbon materials which are amorphism, prepared by the rate of 5.0 ℃/min have higher content of H, ratio of H/C and have better electrochemical performances. 3. The effect of different heat-treated temperature on the microstructure and electrochemical performance is investigated. The results demonstrate that with the increasing heat-treated temperature carbon materials becomes more orderly. Carbon materials prepared at 700℃ have bigger specific surface areas and better electrochemical performances. -III-<WP=7>东北师范大学硕士学位论文 作者：郝婕 4. NaOH can remove the oxide of silicon in RH. The effect of different concentration of NaOH on the microstructure and electrochemical performances is investigated. The results demonstrate that carbon materials get higher content of C and appear (100) diffraction peak with the increasing concentration of NaOH. The carbon materials dealt with 2.0 mol/L NaOH have better electrochemical performances. The carbon material, treated at the rate of 5.0 ℃/min, at 700°C and2.0 mol/L NaOH, have the best results, the first charge and dischargespecific capacity are 678.0 m Ah/g and 239 m Ah/g respectively. The firstcharge-discharge efficiency is 35.2% and is 98.6% after ten cycles.更多还原