Investigation of new manganese orthophosphate Mn₃(PO₄)₂ coating for nickel-rich LiNi_0.6Co_0.2Mn_0.2O₂ cathode and improvement of its thermal properties

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• 作者：Woosuk Cho^a ; Sang-Min Kim^a ; Ko-Woon Lee^a ; Jun Ho Song^a ; Yong Nam Jo^a ; Taeeun Yim^a ; ^b ; Hyuntae Kim^a ; Jeom-Soo Kim^c ; ^{JSenergy@dau.ac.kr" class="auth_mail" title="E-mail the corresponding author} ; Young-Jun Kim^a ; ^{yjkim@keti.re.kr" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Lithium-ion battery ; Nickel-rich layered cathode ; Surface coating ; Manganese orthophosphate ; Thermal stability
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：20 April 2016
• 年：2016
• 卷：198
• 期：Complete
• 页码：77-83
• 全文大小：1539 K

文摘

In this study, manganese orthophosphate (Mn₃(PO₄)₂) is investigated as a new coating material for the Ni-rich LiNi_0.6Co_0.2Mn_0.2O₂ cathode with the aim of improving its thermal properties. A sol–gel process is employed to achieve a uniform coating of nano–sized crystalline Mn₃(PO₄)₂. The coated electrode is found to exhibit an improved rate capability at high current drain, and cycle performance is enhanced at a high temperature of 60 °C. The effect of the Mn₃(PO₄)₂ coating thus formed is further investigated by AC impedance spectroscopy, the results of which confirm that interfacial impedance is significantly decreased even in the initial cycles, and the growth of impedance is successfully suppressed during progressive cycles. The thermal stability of LiNi_0.6Co_0.2Mn_0.2O₂ is also improved by the Mn₃(PO₄)₂ coating, because of the high structural stability attributed to strong PO₄ covalent bonds. On the basis of these results, the Mn₃(PO₄)₂ coating is proposed as a viable surface modification method for the enhancement of the electrochemical and thermal properties of LiNi_0.6Co_0.2Mn_0.2O₂.