High-capacity Li₂Mn_0.8Fe_0.2SiO₄/carbon composite nanofiber cathodes for lithium-ion batteries

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• 作者：Shu Zhang ; Ying Li ; Guanjie Xu ; Shuli Li ; Yao Lu ; Ozan Toprakci ; Xiangwu Zhang ; ^{xiangwu_zhang@ncsu.edu}
• 关键词：Li2MnSiO4 ; Iron doping ; Cathode ; Electrospinning ; Carbon nanofibers
• 刊名：Journal of Power Sources
• 出版年：2012
• 期刊代码：58_03787753
• 类别：ce
• 出版时间：1 September, 2012
• 卷：213
• 期：Complete
• 页码：10-15
• 文件大小：822 K

摘要

Li₂MnSiO₄ has been considered as a promising cathode material with an extremely high theoretically capacity of 332聽mAh聽g^鈭?. However, due to its low intrinsic conductivity and poor structural stability, only about half of the theoretical capacity has been realized in practice and the capacity decays rapidly during cycling. To realize the high capacity and improve the cycling performance, Li₂Mn_0.8Fe_0.2SiO₄/carbon composite nanofibers were prepared by the combination of iron doping and electrospinning. X-ray diffraction, scanning electron microscope, and transmission electronic microscope were applied to characterize the Li₂Mn_0.8Fe_0.2SiO₄/carbon nanofibers. It was found that Li₂Mn_0.8Fe_0.2SiO₄ nanoparticles were embedded into continuous carbon nanofiber matrices, which formed free-standing porous mats that could be used as binder-free cathodes. The iron doping improved the conductivity and purity of the active material, and the carbon nanofiber matrix facilitated ion transfer and charge diffusion. As a result, Li₂Mn_0.8Fe_0.2SiO₄/carbon nanofiber cathodes showed promising improvement on reversible capacity and cycling performance.