In Situ Coupling of Highly Dispersed Ni/Fe <scp>Metal‐NC</scp> Sites and N‐Doped <scp>3D</scp> Carbon Fibers Toward Free‐Standing Bifunctional Cathode for Flexible Zinc‐Air Battery
Chenglong Lai, Mengjun Li, Yi Shen, Min Zhou, Wei Wang, Kai Jiang, Haomiao Li, Kangli Wang
Abstract
Designing flexible free‐standing air‐electrode with efficient OER/ORR performance is of vital importance for the application of Zinc‐air batteries in flexible electronics. Herein, a flexible free‐standing electrode (Ni/Fe‐NC/NCF/CC) is synthesized by in‐situ coupling of binary Ni/Fe‐NC nanocubes and N‐doped carbon nanofibers (NCF) rooted on carbon cloth. The highly dispersed binary Ni/Fe‐NC sites ensure excellent ORR activity and create efficient OER active sites relative to Ni‐NC and Fe‐NC. The in‐situ coupling of Ni/Fe‐NC and NCF constructs a 3D interconnected network structure that not only provides abundant and stabilized reactive sites but also guarantees fast electron transfer and gas transportation, thus achieving efficient and fast operation of ORR/OER. Therefore, Ni/Fe‐NC/NCF/CC displays a much positive potential (0.952 V) at 4.0 mA cm −2 for ORR and a low OER overpotential (310 mV) at 50 mA cm −2 . The Zinc‐air battery with Ni/Fe‐NC/NCF/CC air‐electrode exhibits excellent battery performance with outstanding discharge/charge durability for 2150 cycles. The flexible Zn‐air batteries with foldable mechanical properties display a high power density of 105.0 mW cm −2 . This work widened the way to prepare flexible bifunctional air‐electrode by designing composition/structure and in‐situ coupling.