LiFePO_4-Coated Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2 as Cathode Materials with High Coulombic Efficiency and Improved Cyclability for Li-Ion Batteries
LiFePO_4包覆的Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2锂离子电池正极材料:增强的库伦效率和循环性能

He Lei ¹ Xu Junmin ² ^* Wang Yongjian ¹ Zhang Changjin ³ ^*

文摘	In this work, we present a new design for a surface protective layer formed by a facile aqueous solution process in which a nano-architectured layer of LiFePO_4 is grown on a Li-rich cathode material, Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2. The coated samples are then calcined at 400 or 500 °C for 5 h. The sample after calcination at 400 °C demonstrates a high initial columbic efficiency of 91.9%, a large reversible capacity of 295.0 mAh·g~(-1) at 0.1C (1C = 300 mA·g~(–1)), and excellent cyclability with a capacity of 206.7 mAh·g~(-1) after 100 cycles at 1C. Meanwhile, voltage fading of the coated sample is effectively suppressed by protection offered by a LiFePO_4 coating layer. These superior electrochemical performances are attributed to the coating layer, which not only protects the Li-rich cathode material from side reaction with the electrolyte and maintains the stability of the interface structure, but also provides excess reversible capacity.
其他语种文摘	采用简单水溶液法制备LiFePO_4包覆的Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2富锂正极材料,包覆后的材料分别经过400 °C或500 °C煅烧处理5 h。测试结果显示,400 °C煅烧处理的包覆样品在0.1C (1C = 300 mA·g~(–1))电流密度下充放电时,首次库仑效率可以高达91.9%,同时,首次放电比容量可达到295.0 mAh·g~(–1)。此外,该包覆样品还具有良好的循环性能,在1C电流密度下循环100次放电比容量仍可保持在206.7 mAh·g~(–1)。进一步的研究发现LiFePO_4的包覆不仅可以提高Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2富锂材料的首次库仑效率和循环稳定性能,而且还能够有效抑制材料在充放电过程中的电压衰减。上述电化学性能的有效提升主要归因于LiFePO_4包覆层可以阻碍Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2富锂材料与电解液之间的直接接触,减少副反应的发生,增强材料表面的结构稳定性,同时还可以为富锂材料提供额外的可逆容量。
来源	物理化学学报 ,2017,33(8):1605-1613 【核心库】
DOI	10.3866/pku.whxb201704145
关键词	Lithium-ion battery ; Lithium-rich cathode materials ; LiFePO_4 coating ; High Columbic efficiency ; Cyclability
地址	1. High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, 230031 2. High Magnetic Field Laboratory, Chinese Academy of Sciences, Key Laboratory of Material Physics of Ministry of Education of China, Hefei, 230031 3. High Magnetic Field Laboratory, Chinese Academy of Sciences, Collaborative Innovation Center of Advanced Microstructures, Hefei, 230031
语种	英文
文献类型	研究性论文
ISSN	1000-6818
学科	物理学;化学
基金	supported by the Scientific Research Grant of Hefei Science Center of Chinese Academy of Sciences ; 国家自然科学基金
文献收藏号	CSCD:6050668