@article{Liu2023, 
author = {Yisi Liu and Zongxu Li and Shizhu Wang and Jinnan Xuan and Dongbin Xiong and Lina Zhou and Jianqing Zhou and Jun Wang and Yahui Yang and Yue Du},
title = {Hierarchical porous yolk–shell Co-N-C nanocatalysts encaged in graphene nanopockets for high-performance Zn-air battery},
year = {2023},
journal = {Nano Research},
volume = {16},
number = {7},
pages = {8893-8901},
keywords = {yolk–shell, Zn-air battery, graphene nanopocket, Bi-functional catalysts, zeolitic imidazolate framework (ZIF)-67@ZIF-8},
url = {https://www.sciopen.com/article/10.1007/s12274-023-5593-2},
doi = {10.1007/s12274-023-5593-2},
abstract = {The rational design and preparation of promising cathode electrocatalysts with excellent activity and strong stability for metal-air batteries is a huge challenge. In this work, we innovate an approach of combining solvothermal with high-temperature pyrolysis utilizing zeolitic imidazolate framework (ZIF)-8 and ZIF-67 as the template to synthesize a novel hybrid material of hierarchical porous yolk–shell Co-N-C polyhedron nanocatalysts engaged in graphene nanopocket (yolk–shell Co-N-C@GNP). The obtained catalyst exhibits prominent bifunctional electrocatalytic performance for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in the alkaline condition, in which the half-wave potential is 0.86 V for ORR, and the over-potential for OER is 0.42 V at 10 mA·cm−2. The rechargeable aqueous Zn-air battery fabricated with yolk–shell Co-N-C@GNP cathode deliveries an open circuit voltage (OCV) of 1.60 V, a peak power density of 236.2 mW·cm−2, and excellent cycling stability over 94 h at 5 mA·cm−2. The quasi-solid-state Zn-air battery (ZAB) using yolk–shell Co-N-C@GNP displays a high OCV of 1.40 V and a small voltage gap of 0.88 V in continuous cycling tests at 2 mA·cm−2. This work provides a valuable thought to focus attention on the design of high-efficient bifunctional catalysts with hierarchical porous yolk–shell framework and high-density metal active sites for metal-air battery technologies.}
}