摘要
Rational construction of carbon-based materials with high-efficiency bifunctionality and low cost as the substitute of precious metal catalyst shows a highly practical value for rechargeable Zn-air batteries(ZABs)yet it still remains challenging.Herein,this study employs a simple mixing-calcination strategy to fabricate a high-performance bifunctional composite catalyst composed of N-doped graphitic carbon encapsulating Co nanoparticles(Co@NrC).Benefiting from the core-shell architectural and compositional advantages of favorable electronic configuration,more exposed active sites,sufficient electric conductivity,rich defects,and excellent charge transport,the optimal Co@NrC hybrid(Co@NrC-0.3)presents outstanding catalytic activity and stability toward oxygen-related electrochemical reactions(oxygen reduction and evolution reactions,i.e.,ORR and OER),with a low potential gap of 0.766 V.Besides,the rechargeable liquid ZAB assembled with this hybrid electrocatalyst delivers a high peak power density of 168 mW cm^(−2),a small initial discharge-charge potential gap of 0.45 V at 10 mA cm^(−2),and a good rate performance.Furthermore,a relatively large power density of 108 mW cm^(−2) is also obtained with the Co@NrC-0.3-based flexible solid-state ZAB,which can well power LED lights.Such work offers insights in developing excellent bifunctional electrocatalysts for both OER and ORR and highlights their potential applications in metal-air batteries and other energy-conversion/storage devices.
基金
the Theme-based Scheme(project number:T23-601/17-R)from Research Grant Council,University Grants Committee,Hong Kong SAR,China.
作者简介
Zongping Shao,State Key Laboratory of Materials-Oriented Chemical Engineering,Department of Chemical Engineering,College of Chemical Engineering,Nanjing Tech University,No.30 PuZhu South Rd.,211800 Nanjing,China.Email:shaozp@njtech.edu.cn;Correspondence:Meng Ni,Department of Bldg and Real Estate,Research Institute for Sustainable Urban Development(RISUD)&Research Institute for Smart Energy(RISE),The Hong Kong Polytechnic University,Hung Hom,Kowloon,999077 Hong Kong,China.Email:meng.ni@polyu.edu.hk。
