锂离子电池磷酸锰锂正极材料的制备和电化学性能的研究
发布时间：2018-11-07 18:22
【摘要】：近年来，随着对清洁环境和可持续能源的巨大需求，锂离子电池受到了越来越多的关注。锂离子电池以其高电压、高容量、长寿命、无记忆效应和对环境友好等优点成为电池发展的趋势和研究的热点。 以LiMnPO4为正极材料的电池具有较高的能量密度，因为LiMnPO4理论比容量为170mAh·g-1，相对于Li+/Li的电极电势为4.1V，能量密度约为697Wh kg-1，因此受到了越来越多的关注。此外，该材料的充放电平台也是处在当前通用的碳酸酯基电解质的稳定电化学窗口内。同时，合成LiMnPO4的原料成本低、对环境友好，因此具有较大的应用潜力。 本文使用高温固相法和水热法制备了LiMnPO4/C复合材料，考察了各种因素对LiMnPO4性能的影响，分别确定了最佳的制备工艺。 考察了碳含量、煅烧温度、煅烧时间对LiMnPO4/C复合材料电化学性能的影响，优化出了最佳的合成工艺，当碳包覆量为8wt.%，煅烧温度是650℃，煅烧时间为8h时，所合成的LiMnPO4/C正极复合材料具有最好的电化学性能，在0.1C下的放电比容量为105mAh·g-1。在此基础上，改善了高温固相法，在球磨时加入表面活性剂PVP，球磨后得到了粒径更小，更均匀的前驱体。这有助于得到碳包覆均匀，粒径分布均匀的LiMnPO4/C，最终所制得的LiMnPO4/C在0.1C下的放电比容量为134mAh·g-1。 优化了水热制备LiMnPO4/C正极复合材料的工艺，考察了碳包覆，水热温度，水热时间和CTAB加入量对LiMnPO4/C电化学性能的影响。最终确定最佳的合成条件是：碳含量为8wt.%，，水热温度是190℃，水热时间是24小时，CTAB的用量为LiMnPO4摩尔数的一半。此条件下合成的LiMnPO4/C正极复合材料具有优异的电化学性能，0.05C下的放电比容量为170mAh·g-1，1C下放电比比容量是131mAh·g-1，5C下放电比容量是100mAh·g-1，而且具有良好的循环性能。
[Abstract]:In recent years, with the great demand for clean environment and sustainable energy, lithium ion batteries have attracted more and more attention. Lithium ion batteries have become the trend and research focus of battery development due to their advantages of high voltage, high capacity, long life, no memory effect and environmental friendliness. The battery with LiMnPO4 as cathode material has high energy density, because the theoretical specific capacity of LiMnPO4 is 170mAh g-1 and the potential of electrode is 4.1 V relative to that of Li / Li. Therefore, the energy density of Li / Li is about 697Wh kg-1,. Therefore, more and more attention has been paid to the energy density of the battery. In addition, the charging and discharging platform of this material is also in the stable electrochemical window of the current common carbonate electrolyte. At the same time, the raw material cost of synthesizing LiMnPO4 is low, and it is environmentally friendly, so it has great application potential. In this paper, LiMnPO4/C composites were prepared by high temperature solid state method and hydrothermal method. The effects of various factors on the properties of LiMnPO4 were investigated and the optimum preparation process was determined. The effects of carbon content, calcination temperature and calcination time on the electrochemical properties of LiMnPO4/C composites were investigated. The optimum synthesis process was optimized. When the amount of carbon coating was 8 wt., the calcination temperature was 650 鈩
本文编号：2317206
[Abstract]:In recent years, with the great demand for clean environment and sustainable energy, lithium ion batteries have attracted more and more attention. Lithium ion batteries have become the trend and research focus of battery development due to their advantages of high voltage, high capacity, long life, no memory effect and environmental friendliness. The battery with LiMnPO4 as cathode material has high energy density, because the theoretical specific capacity of LiMnPO4 is 170mAh g-1 and the potential of electrode is 4.1 V relative to that of Li / Li. Therefore, the energy density of Li / Li is about 697Wh kg-1,. Therefore, more and more attention has been paid to the energy density of the battery. In addition, the charging and discharging platform of this material is also in the stable electrochemical window of the current common carbonate electrolyte. At the same time, the raw material cost of synthesizing LiMnPO4 is low, and it is environmentally friendly, so it has great application potential. In this paper, LiMnPO4/C composites were prepared by high temperature solid state method and hydrothermal method. The effects of various factors on the properties of LiMnPO4 were investigated and the optimum preparation process was determined. The effects of carbon content, calcination temperature and calcination time on the electrochemical properties of LiMnPO4/C composites were investigated. The optimum synthesis process was optimized. When the amount of carbon coating was 8 wt., the calcination temperature was 650 鈩
本文编号：2317206
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