Flower-like NiCo2O4–CN as efficient bifunctional electrocatalyst for Zn-Air battery

Abstract

Bifunctional transition metal oxide based electrocatalysts play an important role in oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) for rechargeable metal-air batteries. Herein, we synthesize a kind of three-dimensional (3D) flower-like composite catalyst with NiCo 2 O 4 and N doped carbon (NC) derived from g-C 3 N 4 , under hydrothermal conditions. The best NiCo 2 O 4-CN catalyst shows a hierarchical structure composed of interconnected nanosheets, and exhibits versatile bifunctional ORR/OER electroactivities with a half-wave potential of 0.81 V for ORR and an overpotential of 383 mV for OER under a current density of 10 mA cm −2. The zinc-air battery with the NiCo 2 O 4-CN cathode demonstrates superior peak power density (149.6mW cm-2), excellent capacity performance up to 738.7 mAh g-1 and considerable durability, showing the feasibility of NiCo 2 O 4-CN in electrochemical energy devices.

Three‐Dimensional Electrodes for Oxygen Electrocatalysis

“…In addition, recent studies have shown that bimetallic oxide catalysts exhibit higher activity than single metals. Yu and co-workers [106] developed nitrogen doped carbon incorporated 3D flower-like NiCo 2 O 4 composites by hydrothermal method, whereas the N-doped carbon was obtained by using g-C 3 N 4 as raw materials. Results demonstrate that the 3D electrode exhibited good ORR/OER bi-functional activity with an E 1/2 value of 0.81 V and overpotential of 383 mV to deliver 10 mA cm À 2 .…”

“…One of the key targets for the noble metal-based catalysts is to reduce their loading, and meanwhile, maintain or even increase the overall activities relative to ORR and OER by incorporation of non-precious metal or metal-free composition. Most of the transition metal-based materials (e. g., oxides, [9][10][11] sulfides, [12][13][14][15] spinels, [16][17][18][19] macrocyclic compounds, [20][21][22] perovskites, [23][24][25] metal-NC catalysts, [26][27][28] ) and metal-free materials feature are earth abundant and cheap in price, which can be easily scalable. However, the relatively inferior catalytic activity severely hindered their practical application in energy related devices.…”

Porous Carbon Networks Decorated with Cobalt on CoFe2O4 as an Air‐Breathing Electrode for High‐Capacity Rechargeable Lithium‐Air Batteries: Role of Metallic Cobalt Nanoparticles

“…Recently, spinel oxides (AB 2 O 4, where A and B are transition metal ions) are explored as electrocatalyst for the ORR/OER to use in metal‐air battery. In the spinel structure of AB 2 O 4 formula, the B 3+ and A 2+ metal ions which occupy in the octahedral and tetrahedral sites, respectively, act as reaction centers to promote the ORR/OER rates . However, the spinel‐oxide catalysts are associated with poor cyclability and still limited electrocatalytic activities.…”

Design of Hierarchical Oxide‐Carbon Nanostructures for Trifunctional Electrocatalytic Applications

“…[1,[7][8][9][10][11][12][13][14][15][16][17][18] Heteroatom doped carbon nanostructures are well known for ORR. [2,[19][20][21][22][23][24][25][26][27][28][29] Further, incorporating metal/ alloy improves the ORR activity. [29][30][31] Reports suggest that metal-nitrogen coordination (M-N x ) centers are highly beneficial for ORR and HER.…”

“…[2,[19][20][21][22][23][24][25][26][27][28][29] Further, incorporating metal/ alloy improves the ORR activity. [29][30][31] Reports suggest that metal-nitrogen coordination (M-N x ) centers are highly beneficial for ORR and HER. [32][33][34][35][36][37] Transition metal nanoparticles supported on N-doped carbon have been extensively studied for HER.…”