| 喷雾干燥法制备Li1.2Mn0.4+xNixCr0.4-2xO2及其结构与电化学特征 |
| Preparation, Structure and Electrochemical Properties of Li1.2Mn0.4+xNixCr0.4-2xO2 by Spray-Dry Process |
| 作者 | 单位 | E-mail | | 张茜 | 苏州大学化学电源研究所,江苏省锂电池材料重点实验室,苏州 215006 | | | 贺诗词 | 苏州大学化学电源研究所,江苏省锂电池材料重点实验室,苏州 215006 | | | 刘伟伟 | 苏州大学化学电源研究所,江苏省锂电池材料重点实验室,苏州 215006 | | | 方国清 | 苏州大学化学电源研究所,江苏省锂电池材料重点实验室,苏州 215006 | | | 金子信悟 | 苏州大学化学电源研究所,江苏省锂电池材料重点实验室,苏州 215006 | | | 杨裕生 | 北京防化院,北京 100083 | | | 郑军伟 | 苏州大学化学电源研究所,江苏省锂电池材料重点实验室,苏州 215006 | | | 李德成 | 苏州大学化学电源研究所,江苏省锂电池材料重点实验室,苏州 215006 | lidecheng@suda.edu.cn |
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| 摘要: 利用喷雾干燥法合成了富锂三元正极材料Li1.2Mn0.4+xNixCr0.4-2xO2(x=0,0.05,0.10,0.15,0.20,以下简称为SD1~SD5),并利用XRD,XPS,ICP,TEM,SEM等手段对材料进行结构,元素价态,形貌及电化学性能等方面的表征.SD1~SD5系列样品都具有层状结构,其所含的Cr元素为Cr6+和Cr3+共存,而Ni元素价态为+2.5价,Mn元素为+4价.SD1~SD4样品中由于存在非晶态的Li2CrO4,导致样品表现出强烈的吸湿性.这个问题可通过水洗处理来解决,且水洗处理对于改善该系列材料的电化学性能有明显的效果.SD1~SD5系列样品中,SD1与SD4样品电化学性能较好,以20 mA·g-1的放电电流密度,在4.8~2.0 V电压区间内,首次放电比容量分别为247和220 mA·h·g-1,经过20次充放电循环后,容量保持率分别为73%和78%.高温条件下SD1和SD4样品的首次放电比容量分别增大为256和237 mA·h·g-1,经过20次充放电循环后容量保持率分别为83%和99%.将充放电电压扩展为5.0~2.0 V时,SD4样品首次放电比容量可以达到307 mA·h·g-1. |
| 关键词: 喷雾干燥法 水洗处理 元素价态 电化学性能 Li1.2Mn0.4+xNixCr0.4-2xO2 固溶体体系 |
| 基金项目: 国家自然科学基金(No．20973200)资助项目. |
| Abstract: Li1.2Mn0.4+xNixCr0.4-2xO2 (x=0, 0.05, 0.10, 0.15, 0.20) were synthesized by spray-drying process, which was named as SD1 to SD5, respectively. Their crystal structures, element valences and the electrochemical performances were investigated by XRD, XPS, ICP, SEM and TEM. All compounds have a typical feature of a Li-rich layered solid solution material in terms of their crystal structures, and the valences of Ni and Mn are 2.5+ and 4+, respectively. As to the valence of Cr, both +3 and +6 co-exist in the samples from SD1 to SD4. Moreover, the present of amorphous Li2CrO4 gives rise to the strong hygroscopicity, which should be closed related to the poor electrochemical properties. Sample with water-washed treatment could effectively remove the amorphous Li2CrO4, and consequently improved its electrochemical properties. The washed SD4 has a reversible capacity of 237 mA·h·g-1 and the capacity retention is about 99%, when the cell was operated at 50 ℃ in the range of 4.8~2.0 V. If it was operated in the range of 5.0~2.0 V at 50 ℃, the initial discharge capacity increases to 307 mA·h·g-1. |
| Keywords: spray-dry water-washed oxidation state electrochemical property Li1.2Mn0.4+xNixCr0.4-2xO2 solid-solution |
| 投稿时间：2012-04-19 修订日期：2012-05-18 |
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| 张茜,贺诗词,刘伟伟,方国清,金子信悟,杨裕生,郑军伟,李德成.喷雾干燥法制备Li1.2Mn0.4+xNixCr0.4-2xO2及其结构与电化学特征[J].无机化学学报,2012,28(12):2501-2507. |
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