Bridge-linking interfacial engineering of triple carbons for highly efficient and binder-free electrodes toward flexible Zn-air batteries

Reasonable modulation of catalyst/substrate interface still remains great challenge for binder-free and high-performance electrodes. Herein, interfacial engineering via bridge-linking is proposed to effectively integrate powdery catalysts with flexible substrates by in situ synthesized nanocarbon. Concretely, a binder-free CNTs on carbonized carbon cloth linked with N-doped nanocarbons (CNTs-NC-CCC) electrode is formed via Self-assembly and covalent coupling. Experimental results and theoretical calculation disclose that the bridge-linking strategy not only enables the fast electron and mass transfer, but also modifies the charge distribution and optimizes the adsorption/desorption process of oxygenated intermediates. With these merits, this metal-free catalyst exhibits superb bifunctional ORR/OER electrocatalytic activity with a voltage gap of 0.78 V. Remarkably, when equipped in aqueous and flexible Zn-air batteries, high power density (288, 68 mW cm –2 ) and enhanced durability are obtained. This facile nanocarbon-linkage strategy opens up a new avenue for the application of powdery catalysts in wearable energy devices. Similar to the magpie bridge for the meeting of Cowboy and Weaver in Chinese mythology, in situ synthesized nanocarbon derived from urea based on self-assembly and covalent coupling is a bridge between powdery catalysts and flexible substrates. The obtained flexible binder-free electrode with modulated interface facilitates the fast electron transfer and exhibits superb bifunctional ORR/OER electrocatalytic performances. • Bridge-linking interfacial engineering is proposed by in situ synthesized nanocarbon. • The self-assembly and covalent linkage is the crucial for CNTs-NC-CCC. • Interfacial charge transfer modulates the adsorbability of oxygenated intermediates. • CNTs-NC-CCC exhibits superb bifunctional ORR/OER activities and high-performance of FZABs. • This strategy is facile and universal, providing a unique solution for binder-free electrodes.