Nb5+ doped LiV3O8 nanorods with extraordinary rate performance and cycling stability as cathodes for lithium-ion batteries
Nb5+ doped LiV3O8 nanorods with extraordinary rate performance and cycling stability as cathodes for lithium-ion batteries
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Nb5 掺杂 LiV3O8 纳米棒作为锂离子电池正极具有出色的倍率性能和循环稳定性
DOI：
10.1016/j.electacta.2018.07.149
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发表时间：
2018
影响因子：
6.6
通讯作者：
Gao Yuan
中科院分区：
文献类型：
--
作者：
Wang Liping;Deng Libo;Li Yongliang;Ren Xiangzhong;Mi Hongwei;Sun Lingna;Zhang Peixin;Gao Yuan
正极材料是阻碍锂离子电池发展的关键部件和瓶颈。采用溶胶-凝胶法和静电纺丝法制备了不同Nb掺杂量的LiV 3 O 8纳米棒。Nb掺杂显著提高了LiV 3 O 8的电化学性能。LiV2.94Nb0.06O8在0.1C时的容量为401 mAh g− 1（0.52 mAh cm−2），在20 C时仍保持91 mAh g−1（0.12 mAh cm−2）。掺杂的阴极也显示出优异的循环稳定性，在500次充放电循环后保持其初始容量的99.7%。利用实验技术和基于密度泛函理论（DFT）的理论分析，研究了性能增强的机制。结果表明，Nb的掺杂可以扩展晶格空间，减小禁带宽度，提高本征电导率，降低反应能垒，促进Li离子的吸收和释放动力学。此外，通过静电纺丝获得的纳米棒形态可以缩短锂离子的路径并提供机械稳定性，也是优异性能的原因。
Cathode materials are the key component and bottleneck that hinders the development of lithium-ion batteries. This work reports the preparation of LiV3O8nanorods with different levels of Nb doping through a sol-gel process and a subsequent electrospinning method. The electrochemical performance of LiV3O8as a cathode material was enhanced significantly upon Nb doping. A capacity of 401 mAh g−1at 0.1C (0.52 mAh cm−2) was observed for LiV2.94Nb0.06O8, which still retained a value of 91 mAh g−1(0.12 mAh cm−2) at 20 C. The doped cathode also showed excellent cycling stability, retaining 99.7% of its initial capacity after 500 cycles of charge and discharge. The mechanisms for the performance enhancement were investigated using experimental techniques and theoretical analysis based on density functional theory (DFT). It was found the Nb doping could expand the lattice space, reduce the bandgap, increase the intrinsic conductivity, lower the energy barrier of the reaction and promote the absorption and release kinetics of Li-ions. Furthermore, the nanorod morphology which was obtained by electrospinning, could shorten the pathway of Li-ions and provide mechanical stability and is also responsible for the excellent performance.