Multifunctional carbon nanofibers coated Co-Zn alloy nanoparticles composite for efficient energy conversion and microwave absorption

Considering the energy crisis and environment pollution, it is urgently to develop multifunctional materials to ensure the sustainable development of human society. Core-shell bimetal/carbon composites have at-tracted great attention in microwave absorption or electrochemical energy conversion devices, and the composite can overcome the deficient performance of pure carbon materials or pure metal materials. In this work, we proposed a simple method to prepare N-doped carbon nanofibers coated CoZn alloy nanoparticle composites (CoZn/N-CNFs) using CoZn(OH)X nanowires and melamine as precursors through pyrolysis process. The prepared CoZn/N-CNFs exhibited outstanding catalytic property for oxygen reduction reaction (ORR, half-wave potential of 0.814 V vs RHE) in alkaline solution. The CoZn/N-CNFs acted as cathode in rechargeable Zn-air batteries (ZABs) exhibited high open circuit voltage (1.33 V), large output power density (223.8 mW cm-2), and robust stability (87 h, 6 cycles), surpassing the commercial Pt/C-based ZABs. In addition, as an excellent performance electromagnetic wave absorber, CoZn/N-CNFs exhibited favorable impedance matching and electromagnetic wave absorption ability, which has the RLmin of - 33.93 dB under a thickness of 2.1 mm, and the effective bandwidth (RL < -10 dB) of 4.56 GHz with the matching thickness of 2.2 mm. This composite is expected to be a desired metal/carbon composite for ZABs and electromagnetic absorption. This work provides a simple method for the development of multifunctional materials.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Considering the energy crisis and environment pollution, it is urgent to develop multifunctional materials for the sustainable development of human society. In this study, a simple method was proposed to prepare N-doped carbon nanofibers coated CoZn alloy nanoparticle composites (CoZn/N-CNFs). The prepared CoZn/N-CNFs exhibited outstanding catalytic property for oxygen reduction reaction in alkaline solution and acted as cathode in rechargeable Zn-air batteries with high performance. Additionally, CoZn/N-CNFs showed favorable impedance matching and electromagnetic wave absorption ability, making it a desirable metal/carbon composite for ZABs and electromagnetic absorption.