Co₃O₄ nanoparticles decorated carbon nanofiber mat as binder-free air-cathode for high performance rechargeable zinc-air batteries

Abstract

An efficient, durable and low cost air-cathode is essential for a high performance metal-air battery for practical applications. Herein, we report a composite bifunctional catalyst, Co3O4 nanoparticles-decorated carbon nanofibers (CNFs), working as an efficient air-cathode in high performance rechargeable Zn-air batteries (ZnABs). The particles-on-fibers nanohybrid materials were derived from electrospun metal-ion containing polymer fibers followed by thermal carbonization and a post annealing process in air at a moderate temperature. Electrochemical studies suggest that the nanohybrid material effectively catalyzes oxygen reduction reaction via an ideal 4-electron transfer process and outperforms Pt/C in catalyzing oxygen evolution reactions. Accordingly, the prototype ZnABs exhibit a low discharge-charge voltage gap (e.g. 0.7 V, discharge-charge at 2 mA cm(-2)) with higher stability and longer cycle life compared to their counterparts constructed using Pt/C in air-cathode. Importantly, the hybrid nanofiber mat readily serves as an integrated air-cathode without the need of any further modification. Benefitting from its efficient catalytic activities and structural advantages, particularly the 3D architecture of highly conductive CNFs and the high loading density of strongly attached Co3O4 NPs on their surfaces, the resultant ZnABs show significantly improved performance with respect to the rate capability, cycling stability and current density, promising good potential in practical applications.

Integrating NiCo Alloys with Their Oxides as Efficient Bifunctional Cathode Catalysts for Rechargeable Zinc–Air Batteries

“…[7] Some of them, such as NiCo 2 O 4, [8] C-CoPAN900, [9] CoS x /NS-GN, [10] and (CoO/N-CNTs + NiFe-LDH/CNT) [11] have been further implemented into real air cathodes for rechargeable zinc-air batteries.T hose catalysts that solely contain oxides generally show low activity owing to their self-accumulation and insufficient electrical conductivity. [12] It was believed that combining metal oxides and conductive nanocarbon materials such as graphene and carbon nanotubes is an effective approach to enhancing catalytic activity of oxides, [5,13] through increasing number of available active sites and providing efficient charge transport channels.…”

Platinfreie Nanomaterialien für die Sauerstoffreduktion

“…Co 3 O 4 -Nanostäbchen zeigen eine hçhere Aktivität in der ORR als NPs, [77] was dadurch verursacht wird, dass die Nanostäbchen eine hçhere Oberflä-chendichte von exponierten Co 3+ -Ionen bieten. Es wurde eine Reihe von Cobaltoxiden mit komplexen Nanostrukturen hergestellt, einschließlich geordneter mesoporçser, [78] Kern/ Schale-, [79][80][81] und hohler Architekturen, [82,83] [84] CNTs [85,86] und Graphen gekoppelt werden. [87,88] Einzelheiten hierzu folgen später.…”

Macroscopic‐Scale Three‐Dimensional Carbon Nanofiber Architectures for Electrochemical Energy Storage Devices

“…Hor, Liu, and Zong et al reported an integrated bifunctional catalyst electrode of bifunctional catalytically active Co 3 O 4 NPs decorated CNFs as an efficient O 2 -cathode in high-performance rechargeable Zn-O 2 batteries. [292] The 3D nanohybrid material is prepared by the electrospinning mixture solution of selected polymers and metal salts followed by a thermal treatment and a post annealing process in air at a moderate temperature. The investigation results demonstrate that the nanohybrid material effectively catalyzes ORR via an ideal 4-electron transfer process and outperforms Pt/C toward catalyzing OER in alkaline aqueous electrolyte.…”