| Al3+掺杂对Li2FeSiO4结构和电化学性能影响的研究 |
| Effect of Al3+ Doping on Structure and Electrochemical Performance of Li2FeSiO4 |
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| 摘要: 以CH3COOLi·2H2O、C6H8O7·H2O、FeC6H5O7·5H2O、Al2(SO4)3·18H2O和C8H20O4Si为起始原料，采用水热辅助溶胶凝胶法及二次煅烧合成了Li2Fe1-xAlxSiO4/C(x=0.00、0.01、0.03、0.05)正极材料。用IR、XRD、FE-SEM、EDS等方法对材料的晶体结构进行了表征，用ZetaPAL粒度分析仪测量了其粒径分布范围,用SQUID(超导量子干涉仪)测定了样品的磁性，用恒流充/放电对其电化学性能进行了测试。结果表明：n乙酸锂∶n柠檬酸=4∶1、掺Al3+量为3%，80 ℃回流24 h，350 ℃恒温煅烧5 h，700 ℃恒温13 h，所得试样颗粒集中分布在150 nm左右且未出现团聚。在0.1C(16 mA·g-1)、0.2C、0.5C下的首次放电比容量为127 mAh·g-1、103.6 mAh·g-1和91 mAh·g-1，15次循环后无明显衰减，具有很好的循环稳定性。 |
| 关键词: 正极材料 Li2FeSiO4 Al3+掺杂 磁性测定 粒度分布 |
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| Abstract: Adopting CH3COOLi·2H2O、C6H8O7·H2O、FeC6H5O7·5H2O、Al2(SO4)3·18H2O and C8H20O4Si as starting raw material, Li2Fe1-xAlxSiO4/C(x=0.00, 0.01, 0.03, 0.05) electrode material was prepared by hydrothermal assisted sol-gel method and two-step heating solid-state reaction. The structure of the material was studied by IR, XRD, FE-SEM and EDS. The magnetic performance of the material was tested by superconducting quantum interference device (SQUID) and the distribution of the material′s particle size was measured by ZetaPAL laser particle size analyzer. The results show that the electrochemical performance is desirable when the molar ratio of lithium acetate and citric acid was 4∶1 and the dopant of Al3+ was 3%, and the solution was refluxed at 80 ℃ for 24 h, then dried. The precursor was calcined for 5 h at 350 ℃ and 13 h at 700 ℃, and the size of the composite was about 150 nm and aggregation phenomenon wasn′t found. The discharge capacity of initial cycle is 127 mAh·g-1, 103.6 mAh·g-1 and 91 mAh·g-1 under the ratio of 0.1C (16 mA·g-1), 0.2C and 0.5C, respectively and there is no significant degradation even after 15 times cycling, and the cycle stability of material is very well. |
| Keywords: positive material Li2FeSiO4 Al3+-doped measurement of magnetic property distribution of particle size |
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| 兰建云,赵敏寿,王艳芝,乔玉卿.Al3+掺杂对Li2FeSiO4结构和电化学性能影响的研究[J].无机化学学报,2011,27(8):1497-1502. |
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