Ultrathin Hexagonal 2D Co2GeO4 Nanosheets: Excellent Li-Storage Performance and ex Situ Investigation of Electrochemical Mechanism

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• 作者：Shuaixing Jin ; Gongzheng Yang ; Huawei Song ; Hao Cui ; Chengxin Wang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：November 11, 2015
• 年：2015
• 卷：7
• 期：44
• 页码：24932-24943
• 全文大小：1128K
• ISSN：1944-8252

文摘

Two-dimensional (2D) nanostructures are a desirable configuration for lithium ion battery (LIB) electrodes due to their large open surface and short pathway for lithium ions. Therefore, exploring new anode materials with 2D structure could be a promising direction to develop high-performance LIBs. Herein, we synthesized a new type of 2D Ge-based double metal oxides for lithium storage. Ultrathin hexagonal Co₂GeO₄ nanosheets with nanochannels are prepared by a simple hydrothermal method. When used as LIB anode, the sample delivers excellent cyclability and rate capability. A highly stable capacity of 1026 mAhg^鈥? was recorded after 150 cycles. Detailed morphology and phase evolutions were detected by TEM and EELS measurements. It is found that Co₂GeO₄ decomposed into Ge NPs which are evenly dispersed in amorphous Co/Li₂O matrix during the cycling process. Interestingly, the in situ formed Co matrix could serve as a conductive network for electrochemical process of Ge. Moreover, aggregations of Ge NPs could be restricted by the ultrathin configuration and Co/Li₂O skeleton, leading to unique structure stability. Hence, the large surface areas, ultrathin thickness, and atomically metal matrix finally bring the superior electrochemical performance.