Low-Cost Al2O3 Coating Layer As a Preformed SEI on Natural Graphite Powder To Improve Coulombic Efficiency and High-Rate Cycling Stability of Lithium-Ion Batteries

详细信息    查看全文

• 作者：Tianyu Feng ; Youlong Xu ; Zhengwei Zhang ; Xianfeng Du ; Xiaofei Sun ; Lilong Xiong ; Raul Rodriguez ; Rudolf Holze
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：March 16, 2016
• 年：2016
• 卷：8
• 期：10
• 页码：6512-6519
• 全文大小：628K
• ISSN：1944-8252

文摘

Coulombic efficiency especially in the first cycle, cycling stability, and high-rate performance are crucial factors for commercial Li-ion batteries (LIBs). To improve them, in this work, Al₂O₃-coated natural graphite powder was obtained through a low-cost and facile sol–gel method. Based on a comparison of various coated amounts, 0.5 mol % Al(NO₃)₃ (vs mole of graphite) could bring about a smooth Al₂O₃ coating layer with proper thickness, which could act as a preformed solid electrolyte interface (SEI) to reduce the regeneration of SEI and lithium-ions consumption during subsequent cycling. Furthermore, we examined the advantages of Al₂O₃ coating by relating energy levels in LIBs using density functional theory calculations. Owing to its proper bandgap and lithium-ion conduction ability, the coating layer performs the same function as a SEI does, preventing an electron from getting to the outer electrode surface and allowing lithium-ion transport. Therefore, as a preformed SEI, the Al₂O₃ coating layer reduces extra cathode consumption observed in commercial LIBs.