Improved cycling performance of LiNi_0.8Co_0.15Al_0.05O₂/Al₂O₃ with core-shell structure synthesized by a heterogeneous nucleation-and-growth process

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• 作者：Gaole Dai ; Min Yu ; Fei Shen ; Jiali Cao ; Liang Ni ; Yanbin Chen ; Yuefeng Tang…
• 关键词：Core ; shell ; LiNi0.8Co0.15Al0.05O2/Al2O3 ; A heterogeneous nucleation ; and ; growth process ; Lithium ion battery
• 刊名：Ionics
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：22
• 期：11
• 页码：2021-2026
• 全文大小：1,472 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Electrochemistry
  Materials Science
  Physical Chemistry
  Condensed Matter
  Renewable Energy Sources
  Electrical Power Generation and Transmission
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1862-0760
• 卷排序：22

文摘

Al₂O₃ was successfully coated on LiNi_0.8Co_0.15Al_0.05O₂ cathode material by a heterogeneous nucleation-and-growth process with a core-shell structure for Li-ion battery. X-ray diffraction (XRD) measurements were used to indicate that the crystal structure of LiNi_0.8Co_0.15Al_0.05O₂ had no changes and no impurity phase existed after coating. Scanning electron microscopy (SEM) showed differences of surface morphology between coated and uncoated samples. A thin and bright coating layer was visually observed through transmission electron microscope (TEM). It reveals that the thickness of coating layer is 7 nm approximately. Electrochemical measurements were also carried out. Although the initial discharge capacity of the coated sample decreased, the 1-wt.% Al₂O₃-coated sample showed improved cycling performance at room temperature (25 °C) and elevated temperature (55 °C). It provided higher capacity retention of 71.7 and 70.1 % for 1C at 25 and 55 °C after 100 cycles, in comparison with 55.3 and 55.8 % for the uncoated sample. Meanwhile, interfacial resistance between active material and electrolyte decreased detected by electrochemical impedance spectroscopy (EIS) test. These enhancements in electrochemical characterizations are attributed to the improved stability of interface and the coating layer which served as the physical barriers to protect the active material from electrolyte attack.