Direct Growth of Flower‐Like δ‐MnO2 on Three‐Dimensional Graphene for High‐Performance Rechargeable Li‐O2 Batteries |
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| Authors: | Shuangyu Liu Yunguang Zhu Jian Xie Ying Huo Hui Ying Yang Tiejun Zhu Gaoshao Cao Xinbing Zhao Shichao Zhang |
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| Institution: | 1. State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou, China;2. Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore;3. Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province, Hangzhou, China;4. School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing, China |
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| Abstract: | A challenge still remains to develop high‐performance and cost‐effective air electrode for Li‐O2 batteries with high capacity, enhanced rate capability and long cycle life (100 times or above) despite recent advances in this field. In this work, a new design of binder‐free air electrode composed of three‐dimensional (3D) graphene (G) and flower‐like δ‐MnO2 (3D‐G‐MnO2) has been proposed. In this design, graphene and δ‐MnO2 grow directly on the skeleton of Ni foam that inherits the interconnected 3D scaffold of Ni foam. Li‐O2 batteries with 3D‐G‐MnO2 electrode can yield a high discharge capacity of 3660 mAh g?1 at 0.083 mA cm?2. The battery can sustain 132 cycles at a capacity of 492 mAh g?1 (1000 mAh gcarbon ?1) with low overpotentials under a high current density of 0.333 mA cm?2. A high average energy density of 1350 Wh Kg?1 is maintained over 110 cycles at this high current density. The excellent catalytic activity of 3D‐G‐MnO2 makes it an attractive air electrode for high‐performance Li‐O2 batteries. |
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| Keywords: | Li‐O2 batteries three‐dimensional graphene δ ‐MnO2 electrocatalysis enhanced electrochemical performance |
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