The design of efficient cathode with great cycle performance,high flexibility,and low cost is essential for the commercialization of zinc-air battery(ZAB).Herein,we report the exploration of freestanding bifunctional cathode with rationally designed structures,namely,tiny Co nanoparticles embedded in N-doped carbon nanofiber aerogels,which have desired features including uniform Co dispersity,balanced distribution of N-C species,hierarchically porous structure with increased fraction of meso-to micropores,and moderate amounts of defects.Accordingly,the as-fabricated cathodes exhibit positive half-wave potential of 0.82 V for oxygen reduction and small overpotential of 350 mV at 10 mA cm-2 for oxygen evolution,respectively,which deliver smaller reversible oxygen electrode index(0.76 V)than the commercial Pt/C+RuO2(0.80 V)and most Co-based electrocatalysts ever reported.Impressively,the as-constructed liquid rechargeable ZAB behaves high peak power density(160 mW cm-2),large specific capacity(759.7 mAh g-1 at 10 mA cm-2,tested after 120 h of OCV tests),and robust stability over 277 h.Moreover,the as-assembled quasi-solid-state ZAB using such freestanding cathode represents excellent mechanical flexibility and outstanding cycle performance,regardless of being serviced under extremely bending conditions from 0° to 180°,underscoring their promising applications as durable bifunctional cathode for portable metal-air batteries.

Yu Ma;Ding Chen;Weijun Li;Yapeng Zheng;Lin Wang;Gang Shao;Qiao Liu;Weiyou Yang

College of Materials Science and Engineering,Hunan University,Changsha 410082,China;Institute of Materials,Ningbo University of Technology,Ningbo 315211,China;State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,College of Mechanical and Vehicle Engineering,Hunan University,Changsha 410082,China;School of Materials Science and Engineering,Zhengzhou University,Zhengzhou 450001,China

能源与环境材料（英文）

[1]Yu Ma;Ding Chen;Weijun Li;Yapeng Zheng;Lin Wang;Gang Shao;Qiao Liu;Weiyou Yang-.Highly Dispersive Co@N-C Catalyst as Freestanding Bifunctional Cathode for Flexible and Rechargeable Zinc-air Batteries)[J].能源与环境材料（英文）,2022(02):543-554

C+RuO2

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