Enhancing the Thermal and Upper Voltage Performance of Ni-Rich Cathode Material by a Homogeneous and Facile Coating Method: Spray-Drying Coating with Nano-Al2O3

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• 作者：Ke Du ; Hongbin Xie ; Guorong Hu ; Zhongdong Peng ; Yanbing Cao ; Fan Yu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：July 13, 2016
• 年：2016
• 卷：8
• 期：27
• 页码：17713-17720
• 全文大小：592K
• 年卷期：0
• ISSN：1944-8252

文摘

The electrochemical performance of Ni-rich cathode material at high temperature (>50 °C) and upper voltage operation (>4.3 V) is a challenge for next-generation lithium-ion batteries (LIBs) because of the rapid capacity degradation over cycling. Here we report improved performance of LiNi_0.8Co_0.15Al_0.05O₂ materials via a LiAlO₂ coating, which was prepared from a Ni_0.80Co_0.15Al_0.05(OH)₂ precursor by spray-drying coating with nano-Al₂O₃. Investigations by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy revealed that an Al₂O₃ layer is uniformly distributed on the precursor and a LiAlO₂ layer on the as-prepared cathode material. Such a coating shell acts as a scavenger to protect the cathode material from attack by HF and serious side reactions, which remarkably enhances the cycle performance at 55 °C and upper operating voltage (4.4 and 4.5 V). In particular, the sample with a 2% Al₂O₃ coating shows capacity retentions of 90.40%, 85.14%, 87.85%, and 81.1% after 150 cycles at a rate of 1.0C at room temperature, 55 °C, 4.4 V, and 4.5 V, respectively, which are significantly higher than those of the pristine one. This is mainly due to the significant improvement of the structural stability led by the effective coating technique, which could be extended to other cathode materials to obtain LIBs with enhanced safety and excellent cycling stability.