Electrochemically Formed Ultrafine Metal Oxide Nanocatalysts for High-Performance Lithium–Oxygen Batteries

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• 作者：Bin Liu ; Pengfei Yan ; Wu Xu ; Jianming Zheng ; Yang He ; Langli Luo ; Mark E. Bowden ; Chong-Min Wang ; Ji-Guang Zhang
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：August 10, 2016
• 年：2016
• 卷：16
• 期：8
• 页码：4932-4939
• 全文大小：649K
• 年卷期：0
• ISSN：1530-6992

文摘

Lithium–oxygen (Li–O₂) batteries have an extremely high theoretical specific energy density when compared with conventional energy-storage systems. However, practical application of the Li–O₂ battery system still faces significant challenges. In this work, we report a new approach for synthesis of ultrafine metal oxide nanocatalysts through an electrochemical prelithiation process. This process reduces the size of NiCo₂O₄ (NCO) particles from 20–30 nm to a uniformly distributed domain of ∼2 nm and significantly improves their catalytic activity. Structurally, the prelithiated NCO nanowires feature ultrafine NiO/CoO nanoparticles that are highly stable during prolonged cycles in terms of morphology and particle size, thus maintaining an excellent catalytic effect to oxygen reduction and evolution reactions. A Li–O₂ battery using this catalyst demonstrated an initial capacity of 29 280 mAh g^–1 and retained a capacity of >1000 mAh g^–1 after 100 cycles based on the weight of the NCO active material. Direct in situ transmission electron microscopy observations conclusively revealed the lithiation/delithiation process of as-prepared NCO nanowires and provided in-depth understanding for both catalyst and battery chemistries of transition-metal oxides. This unique electrochemical approach could also be used to form ultrafine nanoparticles of a broad range of materials for catalyst and other applications.