Precisely controllable microwave-driven reconstruction of Ni-Co-Fe trimetallic needle structures on nitrogen-doped carbon as bifunctional oxygen catalysts for Zn–air batteries
Youngsun Cha, Hoyoung Jang, Dowon Noh, Yeonbin Seong, Junyeol Choi, Tae‐Won Kim, Jaewook Seo, Jiheon Kim, Joon Hyung Shim, Yong Tae Kang, Wonjoon Choi
Abstract
Abstract Zinc–air batteries (ZABs) are regarded as promising options for sustainable energy storage due to their high specific energy density, cost-effectiveness, and environmental friendliness. However, their scalability is rendered challenging because of high overpotential, slow kinetics in the bifunctional oxygen evolution reaction/oxygen reduction reaction, and instability in alkaline environments. Herein, we report the development of a highly active bifunctional oxygen catalyst, denoted as TON@NC (trimetallic oxide needles on nitrogen-doped carbon), which consists of Ni-Co-Fe oxide nanoneedles uniformly anchored on a nitrogen-doped carbon network. The synthesis of TON@NC is implemented by a hydrothermal process that creates hydroxide, followed by thermal heating using microwaves. The optimized TON@NC catalyst retains its desirable structural porosity and exhibits exceptional bifunctional oxygen catalytic performance owing to well-designed oxygen vacancies and suitable crystallite sizes. TON@NC demonstrates enhanced performance in oxygen catalytic reactions, with a half-wave potential of 0.78 V and an active potential of 1.49 V in alkaline environments, outperforming carbon-based precious metal catalysts. Furthermore, ZABs employing TON@NC as the air cathode show remarkable cycling stability over 300 h and an outstanding output power density of 100.5 mW cm −2 . This facile and adaptable synthetic strategy can accelerate the development of porous hybrids composed of precisely engineered nitrogen-doped carbon backbones combined with advanced multi-metallic catalysts for energy storage applications. Microwave-assisted reconstruction strategy is devised to fabricate a highly active bifunctional oxygen catalyst, named as TON@NC, in which Ni-Co-Fe trimetallic oxide needles are anchored on nitrogen-doped carbon network structures. TON@NC demonstrates highly enhanced oxygen catalytic reactions, with a half-wave potential of 0.78 V and an active potential of 1.49 V in alkaline environments, while ZABs employing TON@NC as the air cathode show remarkable cycling stability over 300 h and an outstanding output power density of 100.5 mW cm −2 . Graphical Abstract