Anomalous Enhancement of Li-O₂ Battery Performance with Li₂O₂ Films Assisted by NiFeO_x Nanofiber Catalysts: Insights into Morphology Control

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• 作者：Jiaqiang Huang ; Biao Zhang ; Zhaowen Bai ; Ruiqiang Guo ; Zheng-Long Xu ; Zoya Sadighi ; Lei Qin ; Tong-Yi Zhang ; Guohua Chen ; Baoling Huang and Jang-Kyo Kim
• 刊名：Advanced Functional Materials
• 出版年：2016
• 出版时间：December 6, 2016
• 年：2016
• 卷：26
• 期：45
• 页码：8290-8299
• 全文大小：2765K
• ISSN：1616-3028

文摘

It is generally understood that particle-shaped Li₂O₂ is preferred in Li-O₂ batteries (LOBs) because the dominance of Li₂O₂ films may lead to poor electrochemical performance. The influence of Li₂O₂ morphology and its nucleation mechanism are probed by experiments along with the first-principle calculations. It is revealed that the LOBs with Li₂O₂ films deliver unexpectedly improved capacities, longer cycles, and significantly reduced overpotentials assisted by NiFeO_x nanofiber catalysts. The energetically favored Li 2a vacancies under LiO₂-rich conditions, small crystallites, and large contact areas with the electrode/electrolyte explain the anomalous performance enhancement. Li₂O₂ films are formed by a heterogeneous nucleation mechanism and the voltage applied, electrolyte, electrode surface, and use of catalysts are identified as the parameters controlling the mechanisms. The mapped correlations among these parameters shed light on the control of Li₂O₂ morphology for developing high-performance LOBs.