title: Au-nanocrystals-decorated δ-MnO2 as an efficient catalytic cathode for high-performance Li-O2 batteries.
abstract: A Li-O2 battery works based on the reversible formation and decomposition of Li2O2, which is insulating and highly reactive. Designing a catalytic cathode capable of controlling Li2O2 growth recently became a challenge to overcome this barrier. In this work, we present a new design of catalytic cathode by growing porous Au/δ-MnO2 electrocatalyst directly on a conductive substrate. We found that Au/δ-MnO2 can catalyze the directed growth of Li2O2 into a thin/small form, only inside porous δ-MnO2, and along the surface of δ-MnO2 sheets. We proposed the catalytic mechanism of Au/δ-MnO2, where Au plays a critical role in catalyzing the nucleation, crystallization and conformal growth of Li2O2 on δ-MnO2 sheets. Li-O2 batteries with an Au/δ-MnO2 catalytic cathode showed excellent electrochemical performance due to this favorable Li2O2 growth habit. The battery yielded a high capacity of 10,600 mA h g(-1) with a low polarization of 0.91 V at 100 mA g(-1). Superior cycling stability could be achieved in both capacity-limited (500 mA h g(-1), 165 times at 400 mA g(-1)) and unlimited (ca. 3000 mA h g(-1), 50 cycles at 800 mA g(-1)) modes.
authors.affiliation: State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China. xiejian1977@zju.edu.cn.
authors.forename: Shuangyu
authors.initials: S
authors.lastname: Liu
authors.forename: Guoqing
authors.initials: G
authors.lastname: Wang
authors.forename: Fangfang
authors.initials: F
authors.lastname: Tu
authors.forename: Jian
authors.initials: J
authors.lastname: Xie
authors.forename: Hui Ying
authors.initials: HY
authors.lastname: Yang
authors.forename: Shichao
authors.initials: S
authors.lastname: Zhang
authors.forename: Tiejun
authors.initials: T
authors.lastname: Zhu
authors.forename: Gaoshao
authors.initials: G
authors.lastname: Cao
authors.forename: Xinbing
authors.initials: X
authors.lastname: Zhao