Robust bifunctional oxygen electrocatalyst with a "rigid and flexible" structure for air-cathodes
Fu, GT (Fu, Gengtao)[ 1,2 ] ; Jiang, X (Jiang, Xian)[ 1 ] ; Chen, YF (Chen, Yifan)[ 1 ] ; Xu, L (Xu, Lin)[ 1 ] ; Sun, DM (Sun, Dongmei)[ 1 ] ; Lee, JM (Lee, Jong-Min)[ 2 ]*; Tang, YW (Tang, Yawen)[ 1 ]*（唐亚文）
[ 1 ] Nanjing Normal Univ, Sch Chem & Mat Sci, Jiangsu Collaborat Innovat Ctr Biomed Funct Mat, Jiangsu Key Lab New Power Batteries, Nanjing 210023, Jiangsu, Peoples R China
[ 2 ] Nanyang Technol Univ, Sch Chem & Biomed Engn, Singapore 637459, Singapore
NPG ASIA MATERIALS，201807,10,618-629
The development of highly active air-cathodes with robust stability and a low price is of crucial significance for rechargeable Zn-air batteries and remains a great challenge. Herein, for the first time, we report a "rigid and flexible" material consisting of three-dimensional (3D) porous nickel-manganese oxide (Ni6MnO8) coupled with 1D ultrathin Au nanowires (Au-NWs) as an efficient bifunctional oxygen electrocatalyst, adopting alpha-naphthol-Au(III) as a precursor of Au-NWs and pre-formed Ni6MnO8 as a support. Ni6MnO8 acts not only as a robust carbon-free support that is stable in alkaline electrochemical conditions, but also as a highly active component for the oxygen evolution reaction (OER), while flexible Au-NWs contribute to the excellent oxygen reduction reaction (ORR) activity and act as a flexible conductive electronic network. The coupling of Ni6MnO8 and Au-NWs plays a complementary role in the two types of oxygen electrocatalytic reactions. Accordingly, their advantages have been optimally harnessed while overcoming their deficiencies. Moreover, a Zn-air battery assembled with such a rigid and flexible air-cathode has lower charge and discharge overpotentials and a higher cyclic stability than those with a mixed Pt/C+RuO2 catalyst.