Core–Shell Carbon‐Based Bifunctional Electrocatalysts Derived from COF@MOF Hybrid for Advanced Rechargeable Zn–Air Batteries

Abstract

The development of highly active carbon‐based bifunctional electrocatalysts for both the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is highly desired, but still full of challenges in rechargeable Zn–air batteries. Metal organic frameworks (MOFs) and covalent organic frameworks (COFs) have gained great attention for various applications due to their attractive features of structural tunability, high surface area and high porosity. Herein, a core–shell structured carbon‐based hybrid electrocatalyst (H‐NSC@Co/NSC), which contains high density active sites of MOF‐derived shell (Co/NSC) and COF‐derived hollow core (H‐NSC), is successfully fabricated by direct pyrolysis of covalently‐connected COF@ZIF‐67 hybrid. The core–shell H‐NSC@Co/NSC hybrid manifests excellent catalytic properties toward both OER and ORR with a small potential gap (∆E = 0.75 V). The H‐NSC@Co/NSC assembled Zn–air battery exhibits a high power‐density of 204.3 mW cm−2 and stable rechargeability, outperforming that of Pt/C+RuO2 assembled Zn–air battery. Density functional theory calculations reveal that the electronic structure of the carbon frameworks on the Co/NSC shell can be effectively modulated by the embedded Co nanoparticles (NPs), facilitating the adsorption of oxygen intermediates and leading to enhanced catalytic activity. This work will provide a strategy to design highly‐efficient electrocatalysts for application in energy conversion and storage.

Application of metal-organic frameworks, covalent organic frameworks and their derivates for the metal-air batteries

“…Zn-air Co porphyrin@ZIF-67 ZIF-67 ORR [67] Zn-air Ni-MOF/LDH Ni-MOF OER [68] Zn-air Mo-N/C@MoS2 ZIF-8 ORR/OER [71] Zn-air Ni@N-HCGHF Ni-BTC ORR/OER [72] Zn-air Co-SAs@NC ZnCo-ZIFs ORR/OER [74] Zn-air CoNP-PTCOF PTCOF ORR/OER [77] Zn-air H-NSC@Co/NSC COF@ZIF-67 ORR/OER [78] Zn-air pfSAC-Fe COF ORR [79] Zn-air mC-TpBpy-Fe COF ORR [80] Zn-air COFBTC COF ORR [81] Zn-CO2 In/ZnO@C ZIF-8 CO2RR [83] Zn-CO2 Cu3P/C HKUST-1 CO₂ RR [85] Zn-CO2 ZnTe/ZnO@C ZnTe-MOF…”

Interfacial Engineering of Leaf-like Bimetallic MOF-Based Co@NC Nanoarrays Coupled with Ultrathin CoFe-LDH Nanosheets for Rechargeable and Flexible Zn-Air Batteries

“…Concurrently, electronics are developing towards portability and flexibility in recent years, posing a major challenge to flexible wearable energy storage devices [ 5 , 6 , 7 ]. As one of the next-generation alternative energy technologies, rechargeable Zn-air batteries (ZABs) have broad application prospects in future electric vehicles, portable electronic products, flexible wearable electronic devices, and off-grid power supplies due to their large theoretical energy density, high safety, abundant resources, and environmental amity [ 6 , 8 , 9 ]. Nevertheless, the actual energy efficiency and cycling performance of ZABs are still far from satisfactory at this time, which is attributed to the poor reactivity of oxygen evolution reduction (OER) and oxygen reduction reaction (ORR) on the air cathode during the charge-discharge process [ 10 , 11 , 12 , 13 , 14 ].…”

Dopamine-coated layered Co0.85Se as an efficient bifunctional oxygen electrocatalyst

“…[6][7][8] However, the sluggish kinetics and complex multi-electron transfer pathways slow down these processes, thus requiring efficient electrocatalysts to reduce the excessively large overpotentials. [9][10][11][12] Current commercially available OER and ORR catalysts are based on platinum group metals (PGMs), like Pt, Ru, Ir, and Rh. [13][14][15][16] On the one hand, the high cost and scarcity seriously hinder their widespread application.…”