Flakelike LiCoO2 with Exposed {010} Facets As a Stable Cathode Material for Highly Reversible Lithium Storage

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• 作者：Naiteng Wu ; Yun Zhang ; Yi Guo ; Shengjie Liu ; Heng Liu ; Hao Wu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：February 3, 2016
• 年：2016
• 卷：8
• 期：4
• 页码：2723-2731
• 全文大小：622K
• ISSN：1944-8252

文摘

A thick and dense flakelike LiCoO₂ with exposed {010} active facets is synthesized using Co(OH)₂ nanoflake as a self-sacrificial template obtained from a simple coprecipitation method, and served as a cathode material for lithium ion batteries. When operated at a high cutoff voltage up to 4.5 V, the resultant LiCoO₂ exhibits an outstanding rate capability, delivering a reversible discharge capacity as high as 179, 176, 168, 116, and 96 mA h g^–1 at 25 °C under the current rate of 0.1, 0.5, 1, 5, and 10 C, respectively. When charge/discharge cycling at 55 °C, a high specific capacity of 148 mA h g^–1 (～88% retention) can be retained after 100 cycles under 1 C, demonstrating excellent cycling and thermal stability. Besides, the flakelike LiCoO₂ also shows an impressive low-temperature electrochemical activity with specific capacities of 175 (0.1 C) and 154 mA h g^–1 (1 C) at ?10 °C, being the highest ever reported for a subzero-temperature lithium storage capability, as well as 52% capacity retention even after 80 cycles under 1 C. Such superior high-voltage electrochemical performances of the flakelike LiCoO₂ operated at a wide temperature range are mainly attributed to its unique hierarchical structure with specifically exposed facets. The exposed {010} active facets provide a preferential crystallographic orientation for Li-ion migration, while the micrometer-sized secondary particles agglomerated by submicron primary LiCoO₂ flakes endow the electrode with better structural integrity, both of which ensure the LiCoO₂ cathode to manifest remarkably enhanced reversible lithium storage properties.