| 稀土Sm掺杂LiFePO4/C正极材料的结构和电化学性能 |
| Structure and Electrochemical Properties of Sm-Doped Lithium Iron Phosphate Cathode Materials |
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| 摘要: 采用高温固相法制备LiFe1-xSmxPO4 /C(x=0，0.06，0.08，0.10)锂离子电池正极材料，并用XRD，SEM，CV及EIS等方法进行结构和电化学性能的测试。结果表明，通过该法制得的样品均具有橄榄石型晶体结构。Sm的掺杂可明显细化颗粒，并导致LiFePO4晶格中c轴方向的P-O键长增加，其中x=0.08样品P-O键长最大(0.152 8 nm)，明显大于未掺杂样品的键长(0.142 2 nm)。电化学性能测试表明，掺杂后LiFePO4的放电容量增加，循环稳定性能提高。在-20~40 ℃的温度区间内，放电容量随温度的升高而增加，其中x=0.08的样品40 ℃时放电容量为159 mAh·g-1，但测试温度达到60 ℃时，放电容量急剧下降。EIS测试表明Sm的掺杂可以明显改善电极表面电化学反应的动力学性能，降低电荷转移电阻，提高交换电流密度。 |
| 关键词: 磷酸亚铁锂 稀土Sm 正极材料 锂离子电池 |
| 基金项目: |
| Abstract: Microstructure and electrochemical properties of LiFe1-xSmxPO4 /C(x=0, 0.06, 0.08, 0.10) have been investigated using XRD, SEM, CV, EIS measurements. All the samples have the crystal structure of olivine. With increasing Sm substitution content, the particles of synthesized LiFe1-xSmxPO4 /C are fine and homogeneous in size. The optimal doping content of Sm is that x=0.08 in the LiFe1-xSmxPO4 /C samples to achieve high discharge capacity and good cycle performances. The temperature effect indicates that the discharge capacity increases with the rise of temperature in -20~40 ℃. The sample with x=0.08 delivers the discharge capacity of 159 mAh·g-1 at 40 ℃, while the discharge capacity decreases drastically at 60 ℃. EIS test demonstrates that the doping of Sm can improve the dynamic performance, decreases the charge transfer resistance Rct and increases the exchange current density i0 greatly. |
| Keywords: lithium iron phosphate Sm cathode lithium-ion battery |
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| 张秋明,乔玉卿,赵敏寿,王立民.稀土Sm掺杂LiFePO4/C正极材料的结构和电化学性能[J].无机化学学报,2012,28(1):67-73. |
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