High rate micron-sized niobium-doped LiMn_1.5Ni_0.5O₄ as ultra high power positive-electrode material for lithium-ion batteries

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• 作者：Ting-Feng Yi^a ; ^{tfyihit@163.com} ; Ying Xie^b ; ^{xieying@hlju.edu.cn} ; Yan-Rong Zhu^a ; Rong-Sun Zhu^a ; Ming-Fu Ye^a
• 关键词：Lithium-ion battery ; Positive-electrode material ; Spinel lithium manganese nickel oxide ; Niobium doping ; Rate-performance
• 刊名：Journal of Power Sources
• 出版年：2012
• 期刊代码：58_03787753
• 类别：ce
• 出版时间：1 August, 2012
• 卷：211
• 期：Complete
• 页码：59-65
• 文件大小：854 K

摘要

Nb-doped LiMn_1.5Ni_0.5O₄ materials have been synthesized through a solid-state reaction, and Nb doping achieves some encouraging results. Both crystal domain size and electronic conductivity are influenced by this kind of doping. The lattice parameter of the Nb-doped LiMn_1.5Ni_0.5O₄ samples are slightly larger than that of pure LiMn_1.5Ni_0.5O₄ samples, and Nb doping does not change the basic spinel structure. Even聽though the material has a particle size of 1-2聽渭m, the capacity retention is improved remarkably compared to that of the undoped one when charge-discharged at high rates. The LiNi_0.525Mn_1.425Nb_0.05O₄ has a discharge capacity of 102.7聽mAh聽g^鈭? at 1 C charge-discharge rate after 100 cycles. Though all samples exhibit similar initial discharge capacities at various high C rates, the Nb-doped LiMn_1.5Ni_0.5O₄ samples display remarkable cyclabilities. Capacity retention of Nb-doped LiMn_1.5Ni_0.5O₄ is excellent without a significant capacity loss at various high C rates. This is ascribed to a smaller crystallite, a higher conductivity, and a higher lithium diffusion coefficient (D_Li) observed in this material. As a result, our microscale Nb-doped LiMn_1.5Ni_0.5O₄ can be used for battery applications that require high power and long life, including HEVs and energy storage devices for renewable energy systems.