Towards high-performance cathode materials for lithium-ion batteries: Al2O3-coated LiNi0.8Co0.15Zn0.05O2
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Zn-doped LiNi0.8Co0.2O2 exhibits impressive electrochemical performance but suffers limited cycling stability due to the relative large size of irregular and bare particle which is prepared by conventional solid-state method usually requiring high calcination temperature and prolonged calcination time. Here, submicron LiNi0.8Co0.15Zn0.05O2 as cathode material for lithium-ion batteries is synthesized by a facile sol-gel method, which followed by coating Al2O3 layer of about 15 nm to enhance its electrochemistry performance. The as-prepared Al2O3-coated LiNi0.8Co0.15Zn0.05O2 cathode delivers a highly reversible capacity of 182 mA h g−1 and 94% capacity retention after 100 cycles at a current rate of 0.5 C, which is much superior to that of bare LiNi0.8Co0.15Zn0.05O2 cathode. The enhanced electrochemistry performance can be attributed to the Al2O3-coated protective layer, which prevents the direct contact between the LiNi0.8Co0.15Zn0.05O2 and electrolyte. The escalating trend of Li-ion diffusion coefficient estimated form electrochemical impedance spectroscopic (EIS) also indicate the enhanced structural stability of Al2O3-coated LiNi0.8Co0.15Zn0.05O2, which rationally illuminates the protection mechanism of the Al2O3-coated layer.
KeywordsLiNi0.8Co0.15Zn0.05O2 Al2O3 Cathode Lithium-ion batteries Electrochemical impedance spectroscopic
We thank Analytical and Testing Center of Huazhong University of Science and Technology and the Center of Micro-Fabrication and Characterization (CMFC) of WNLO for use of their facilities.
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