Highly efficient Co3O4/Co@NCs bifunctional oxygen electrocatalysts for long life rechargeable Zn-air batteries. (November 2020)

• Record Type: Journal Article
• Authors: Yu, Neng-Fei; Wu, Chang; Huang, Wen; Chen, You-Hu; Ruan, Da-Qian; Bao, Kai-Lin; Chen, Hui; Zhang, Yi; Zhu, Yusong; Huang, Qing-Hong; Lai, Wei-Hong; Wang, Yun-Xiao; Liao, Hong-Gang; Sun, Shi-Gang; Wu, Yu-Ping; Wang, Jiazhao
• Is Part Of: Nano energy. Volume 77(2020)
• Publication Date: 2020-11
• Subjects: Bifunctional oxygen electrocatalysts -- Nano-heterostructured interfaces -- Metal–organic frameworks -- Electrocatalysis -- Rechargeable Zn–air batteries; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2020.105200
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Rational design and synthesis of high-performance bifunctional oxygen electrocatalysts are in high demand for metal air batteries. Herein, Co3 O4 /Co nano-heterojunctions tailored in nitrogen-doped porous graphitized carbon frameworks (Co3 O4 /Co@NCs) are synthesized via annealing Co-based metal-organic-frameworks (Co-based MOFs). This structure for electrocatalysts with a combination of mixed metallic Co species and encapsulating porous graphitized carbon offers an efficient charge/mass transport environment. In addition, the Co3 O4 /Co nano-heterostructured interfaces serve as efficient reactive sites to enhance oxygen electrocatalysis. Furthermore, the strong binding forces between nanoparticles and carbon frameworks through Co–N covalent bonds prevent the loss of nanoparticles from the electrocatalysts, providing outstanding durability. Consequently, Co3 O4 /Co@NCs surpasses the performance of noble-metal catalysts with a positive half-wave potential of 0.92 V (vs. reversible hydrogen electrode, RHE) for the oxygen reduction reaction and a low potential of 1.55 V at 10 mA cm −2 for the oxygen evolution reaction. Impressively, our assembled zinc–air batteries using Co3 O4 /Co@NCs as the rechargeable air electrode exhibit superior charge-discharge performance and ultra-stable cyclability with almost no increase in polarization even after 600 h (10 mA cm −2 ), possessing great potential for practical application in next-generation rechargeable batteries. Graphical abstract: Image 1 Highlights: The Co3 O4 /Co@NCs catalyst with Co3 O4 /Co nano heterojunctions encapsulated in nitrogen doped porous carbon was synthesized. The Co3 O4 /Co@NCs demonstrated as an efficient bifunctional electrocatalyst to ORR (exceeding Pt/C) and OER (surpassing Ir/C). The Zn-air batteries with Co3 O4 /Co@NCs cathode deliver a high power density and ultra-stable cyclability.