| 溶胶凝胶-软模板法制备LiNi1/3Co1/3Mn1/3O2正极材料及其电化学性能研究 |
| Preparation and Electrochemical Properties of LiNi1/3Co1/3Mn1/3O2 Cathode Material by Soft Template Assisted Sol-Gel Method |
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| 摘要: 在溶胶凝胶法中引入了软模板十二烷基磺酸钠(SDS)制备了LiNi1/3Co1/3Mn1/3O2正极材料。采用X射线衍射法(XRD)，扫描电镜法(SEM)，循环伏安法(CV)，交流阻抗法(EIS)及充放电测试等手段对材料进行了表征。结果表明，在750 ℃下煅烧12 h加入或不加SDS都能得到结晶较好具有六方层状α-NaFeO2结构的LiNi1/3Co1/3Mn1/3O2。SEM显示引入SDS辅助制备的目标材料颗粒细小，约60～300 nm，分散均匀，部分颗粒呈类球状形貌。而没有添加表面活性剂制备的材料粒径范围约250～600 nm，并且部分颗粒有团聚现象。在2.8～4.3 V(vs Li/Li+)，0.5C倍率下，SDS辅助制备和没有添加表面活性剂制备的材料首次放电比容量分别为136.8、123.4 mAh·g-1，50次循环后容量保持率分别为90.3%，73.8%。2C和5C下的充放电测试结果都显示SDS的加入能有效改善材料的倍率性能。归因于颗粒更细小，分散更均匀及较小的晶胞体积，SDS辅助制备的材料电荷传递阻抗远小于无表面活性剂辅助制备的材料是其倍率性能得到明显提高的重要原因。 |
| 关键词: 锂离子电池 LiNi1/3Co1/3Mn1/3O2 溶胶凝胶-软模板法 十二烷基磺酸钠 倍率性能 |
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| Abstract: Soft template (sodium dodecyl sulfonate, SDS) assisted Sol-Gel method was provided in this paper to obtain LiNi1/3Co1/3Mn1/3O2 cathode material. Related characters of products were investigated by X-ray diffraction (XRD), scanning electron macroscopy (SEM), cyclic voltametry (CV), electrochemical impedance spectroscopy (EIS) and charge-discharge testing. XRD results showed that the samples with SDS and without surfactant caclined 750 ℃ for 12 h both were indexed to pure LiNi1/3Co1/3Mn1/3O2 with well hexagonal structure (α-NaFeO2). As observed by SEM, the particle sizes of those with SDS surfactant and without surfactant were in a range of 60～300 nm and 250～600 nm, respectively. Meanwhile, the particle distribution of that with SDS was more uniform than that of without surfactant. It′s also observed that material prepared without surfactant showed some agglomeration. Initial discharge capacity of 136.8 mAh·g-1 with the capacity retention of 90.3% after 50 cycles in the range 2.8～4.3 V (vs Li/Li+) and at 0.5C for LiNi1/3Co1/3Mn1/3O2 prepared with SDS was obtained in this paper, while for the sample that prepared without surfactant, its initial discharge capacity was about 123.4 mAh·g-1 and the capacity retention was about 73.8%. Moreover, the comparison of electrochemical results at 2C and 5C indicated that the sample with SDS had obviously improved rate capacity. Owning to much smaller particle, more uniform particle distribution and smaller crystal cell volume, compared with that without surfactant, less change of charge transfer resistance was considered as the main reason why rate capability of LiNi1/3Co1/3Mn1/3O2 prepared with SDS improved obviously. |
| Keywords: Lithium ion battery LiNi1/3Co1/3Mn1/3O2 soft template assisted sol-gel method sodium dodecyl sulfonate rate capability |
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| 王海燕,黄可龙,刘素琴,罗 燕.溶胶凝胶-软模板法制备LiNi1/3Co1/3Mn1/3O2正极材料及其电化学性能研究[J].无机化学学报,2009,25(12):2090-2096. |
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