MoO42-取代对Nasicon型Li3Fe2(PO4)3正极材料电化学性能的影响
Effect of MoO42- Substitution on Electrochemical Properties of Nasicon Li3Fe2(PO4)3 Cathode
作者单位E-mail
张勃 河北工业大学, 材料科学与工程学院, 天津 300130  
何珺 河北工业大学, 材料科学与工程学院, 天津 300130  
华正伸 河北工业大学, 材料科学与工程学院, 天津 300130  
鲁豪祺 河北工业大学, 材料科学与工程学院, 天津 300130  
王新 河北工业大学, 材料科学与工程学院, 天津 300130  
彭会芬 河北工业大学, 材料科学与工程学院, 天津 300130
天津市材料层状复合与界面控制技术重点实验室, 天津 300130 
peng@hebut.edu.cn 
摘要: 以MoO42-部分取代Li3Fe2(PO43中的PO43-,研究表明:加入的MoO42-离子主要以固溶形式存在于Li3Fe2(PO43中,起到了显著改善其电化学性能的作用。其中,MoO42-掺杂浓度为0.3的样品表现出最佳的电化学性能,其在0.5C倍率下的首次放电容量为113.7 mAh·g-1,这一数值比未掺杂的提高了20.7%;经过60次循环充放电,容量保持率为94%。将放电倍率从0.5C逐步增大至5C,再降至初始的0.5C,并在每个倍率循环10次,这一材料的最终放电容量可达首次0.5C的95%。这些优异的性能应归因于MoO42-掺杂使材料的氧化还原能力增强,氧化还原电对的电势差减小,电池内部的电荷转移电阻减小,以及Li+扩散系数增加。
关键词: 正极材料  锂电池  混合阴离子效应  阴离子掺杂  电化学性能
基金项目: 河北省自然科学基金(No.E2016202358)资助项目。
Abstract: MoO42- polyanion was tried to substitute for PO43- partially in the Li3Fe2(PO4)3 compound. The results proved that the introduced MoO42- anions mainly dissolved in the Li3Fe2(PO4)3 and the corresponding electrochemical properties were improved apparently. Among the MoO42- substituted materials, the sample with MoO42- content of 0.3 presented the excellent electrochemical properties. Its initial discharging capacity was 113.7 mAh·g-1 at a rate of 0.5C, which was about 20.7% higher than that without any MoO42-. The capacity retention was about 94% at a rate of 0.5C after 60 cycles. Moreover, this material could restore 95% of the initial capacity when the discharging rate was reset back to 0.5C even after higher cycling rate of 5C. The boost in electrochemical properties for the MoO42- substituted samples is ascribed to the synergistic effects of improved redox ability, decreased potential polarization and charge transfer resistance as well as increased diffusion coefficient of lithium ions.
Keywords: cathode  lithium battery  mixed anion effect  anion substitution  electrochemical properties
投稿时间:2016-05-19 修订日期:2016-09-19
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张勃,何珺,华正伸,鲁豪祺,王新,彭会芬.MoO42-取代对Nasicon型Li3Fe2(PO4)3正极材料电化学性能的影响[J].无机化学学报,2016,32(12):2109-2116.
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