High‐Performance Oxygen Reduction Electrocatalyst Derived from Polydopamine and Cobalt Supported on Carbon Nanotubes for Metal–Air Batteries

Abstract

The development of nonprecious metal‐based electrocatalysts for the oxygen reduction reaction holds the decisive key to many energy conversion devices. Among several potential candidates, transition metal and nitrogen co‐doped carbonaceous materials are the most promising, yet their activity and stability are still insufficient to meet the needs of practical applications. In this study, a core–shell hybrid electrocatalyst is developed via the self‐polymerization of dopamine and cobalt on carbon nanotubes (CNTs), followed by high‐temperature pyrolysis. The polymer‐derived carbonaceous shell contains abundant structural defects and facilitates the formation of CoN/C active sites, whereas the graphitic carbon nanotube core provides high electrical conductivity and corrosion resistance. These two components separately fulfill different functionalities, and jointly afford the catalyst with excellent electrochemical performance. In 1 m KOH, CoN/CNT exhibits a positive half‐wave potential of ≈0.91 V, low peroxide yield of <7%, as well as great stability. When used as the air catalyst of primary Zn–air and Al–air batteries, this hybrid electrocatalyst enables large discharge current density, high peak power density, and prolonged operation stability.

Recent Advances toward the Rational Design of Efficient Bifunctional Air Electrodes for Rechargeable Zn–Air Batteries

“…Recently, hybrid materials with transition metals (TMs) encapsulated in graphitic layers ( Figure a,b) are found to be as efficient electrocatalysts to facilitate both ORR and OER, the Fe, Ni, and Co single metal nanoparticles or their combination encapsulated in graphene layers or carbon nanotubes are most special . Transition‐metal nanoparticles could serve multiple purposes at the same time to influence the surface carbon layer, including increasing its graphitization degree during carbonization, and transferring electron to it.…”

Single Fe Atom on Hierarchically Porous S, N‐Codoped Nanocarbon Derived from Porphyra Enable Boosted Oxygen Catalysis for Rechargeable Zn‐Air Batteries

“…Currently, the traditional precursor of Fe‐N‐C materials such as 2, 2‐bipyridine, dicyandiamide, polypyrrole, the metal‐amino acid, graphene, and CNTs, has disadvantages of being cumbersome and pricey, which significantly hampers its pursuable commercialization. To solve these problems, more and more researchers have turned to earth‐abundant and low‐cost biomass‐derived carbons, such as keratin, butterfly wing, yeast, honeysuckles, polydopamine, Vitamin B12, monkey grass, etc. Among them, porphyra has been proved to be an excellent precursor material for electrocatalysis and lithium‐ion batteries due to its inherent heteroatom doping advantages .…”

Defective N/S‐Codoped 3D Cheese‐Like Porous Carbon Nanomaterial toward Efficient Oxygen Reduction and Zn–Air Batteries

“…Fuel cells or metal–air batteries (e.g., Zn–air batteries) are considered as the feasible future energy sources on account of their high theoretical energy density, nonpollution, and safety . Among them, oxygen reduction reaction (ORR) is the rate‐determining step resulting from its high overpotential, low exchange current density, and sluggish kinetic process, seriously restricting overall efficiency because of the suboptimal performance of electrocatalysis . The most commonly used catalysts for ORR are platinum‐based catalysts which have an excessively high price, scarce resource, unsatisfactory durability, and poor poison tolerance, fundamentally impeding the commercialization process of these energy devices .…”