American Chemical Society
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Metallurgy Inspired Formation of Homogeneous Al2O3 Coating Layer To Improve the Electrochemical Properties of LiNi0.8Co0.1Mn0.1O2 Cathode Material

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journal contribution
posted on 2017-09-25, 00:00 authored by Mingxia Dong, Zhixing Wang, Hangkong Li, Huajun Guo, Xinhai Li, Kaimin Shih, Jiexi Wang
Inspired by the metallurgical process of aluminum production, a controllable and cost-effective Al2O3 coating strategy is introduced to improve the surface stability of LiNi0.8Co0.1­Mn0.1O2. The CO2 is introduced to NaAlO2 aqueous solution to generate a weak basic condition that is able to decrease the deposition rate of Al­(OH)3 and is beneficial to the uniform coating of Al­(OH)3 on the surface of commercial Ni0.8Co0.1­Mn0.1(OH)2 precursor. The electrochemical performance of Al2O3-coated LiNi0.8Co0.1­Mn0.1O2 is improved at both ordinary cutoff voltage of 4.3 V and elevated cutoff voltage of 4.5 V. With the optimized Al2O3 coating amount (1%), the capacity retention of the material after 60 cycles increases from 90% to 99% at 2.8–4.3 V and from 86% to 99% at 2.8–4.5 V, respectively. The Al2O3-coated sample also delivers a better rate capability, maintaining 117 and 131 mA h g–1 in the voltage ranges 2.8–4.3 and 2.8 V–4.5 V at the current density of 5 C, respectively. The enhanced properties of as-prepared Al2O3-coated LiNi0.8Co0.1Mn0.1O2 are due to the Al2O3 coating layer building up a favorable interface, preventing the direct contact between the active material and electrolyte and promoting Li+ transmission at the interface.