Based on First-principles Calculation, Study on the Synthesis and Performance of Fe–Ni Co-doped LiMnPO4/C as Cathode Material for Lithium-ion Batteries
Based on First-principles Calculation, Study on the Synthesis and Performance of Fe–Ni Co-doped LiMnPO4/C as Cathode Material for Lithium-ion Batteries
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基于第一性原理计算的Fe-Ni共掺杂LiMnPO4/C锂离子电池正极材料的合成及性能研究
DOI：
10.1007/s11581-021-04344-y
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发表时间：
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期刊：
影响因子：
2.8
通讯作者：
Luo Shanghua
中科院分区：
文献类型：
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作者：
Chang Longjiao;Luo Shanghua
橄榄石结构的LiMnPO4具有原料丰富、价格低廉、结构稳定、能量密度高、循环稳定性好等特点，是锂离子电池正极材料中极具应用前景的材料之一。利用材料工作室软件对LiMn1-x-yFexNiyPO4(x= 0，y= 0；x= 1/4，y= 1/4)体系的电子结构进行了计算。计算结果表明，LiMn1/2Fe1/4Ni1/4PO4/C体系的禁带宽度为0.105 eV，与LiMnPO4相比有很大变化。由此推测，Fe-Ni共掺杂的LiMnPO4材料具有较好的电化学性能。采用共沉淀法合成了LiMn1-x-yFexNiyPO4(x= 0，y= 0；x= 1/4，y= 1/4)复合材料，并探索了最佳合成条件。电化学测试表明，LiMn1/2Fe1/4Ni1/4PO4/C正极材料具有优良的电化学性能，其首次充放电容量为143.8 mAh/g，明显高于LiMnPO4材料。该样品在0.05C倍率下循环100次，放电容量保持在152mAh/g左右，表现出良好的循环稳定性。理论计算和实验测试的结果相互印证，从而制备出具有优异电化学性能的LiMn1/2Fe1/4Ni1/4PO4/C材料。
Olivine-structured LiMnPO4is one of the cathode materials with great application prospects for lithium-ion batteries in that it possesses the characteristics of abundant raw materials, low price, stable structure, high energy density, and good cycling stability. In this paper, the electronic structure of LiMn1-x-yFexNiyPO4(x= 0,y= 0;x= 1/4,y= 1/4) system is calculated by using MS (Material Studio) software. The calculated results show that the band gap width of LiMn1/2Fe1/4Ni1/4PO4/C system is 0.105 eV, which has a great change compared with LiMnPO4. Thus, it is speculated that the Fe–Ni co-doped LiMnPO4material has better electrochemical performance. The LiMn1-x-yFexNiyPO4(x= 0,y= 0;x= 1/4,y= 1/4) composite materials were synthesized by co-precipitation method, and the optimum synthesis conditions also was explored. The electrochemical test indicates that the LiMn1/2Fe1/4Ni1/4PO4/C cathode material has excellent electrochemical properties, and its initial charge–discharge capacity is 143.8 mAh/g, which is significantly higher than that of LiMnPO4material. The discharge capacity of this sample remains at about 152 mAh/g after 100 cycles at 0.05 C rate, showing good cyclic stability. The results of theoretical calculation and experimental test confirm each other, so as to prepare the LiMn1/2Fe1/4Ni1/4PO4/C materials with excellent electrochemical performance.