Regulating the Catalytically Active Sites in Low-Cost and Earth-Abundant 3d Transition-Metal-Based Electrode Materials for High-Performance Zinc–Air Batteries

Abstract

The rapidly increasing demand for clean and efficient energy devices is a critical issue for the sustainable development of human society. The green and low-cost aqueous zinc–air batteries (ZABs) with high theoretical energy density are therefore drawing increasing attention. As the key materials in the air cathode, electrocatalysts that catalyze the oxygen evolution/reaction reactions (OER and ORR) significantly determine the performance of ZABs. Therefore, exploring economic and efficient oxygen catalysts is of great importance for the practical application of ZABs. Among the numerous electrocatalysts, the earth-abundant 3d transition-metal-based nanomaterials have been widely explored as a result of their low cost and high activities. This review introduces some typical and recent progresses in 3d metal-based oxygen catalysts (i.e., metals, metal compounds, and carbon-supported hybrids) for ZABs. Especially, the active sites for catalyzing OER/ORR of different catalysts are classified, and the strategies for regulating the catalytic sites and their reaction mechanism are also introduced. In the end, the challenges and perspectives for further developing 3d metal-based oxygen catalysts are briefly discussed. This review aims to provide inspirations for the exploration of low-cost and efficient electrocatalysts as cathodes for ZABs.

Carbon Nanofibers as Potential Catalyst Support for Fuel Cell Cathodes: A Review

“…Considerable research has been undertaken in the past decade to discover alternative, cost-effective ORR catalysts made up of transition metals such as Fe, Co, Ni, and Mn, especially in combination with the N-doped carbons, which generate potentially ORR active sites, namely M-N-C. − S. G. Peera et al synthesized a durable GNF catalyst by the deposition of Fe and Co species on the N-F/GNF catalysts (Fe-Co/NF-GNF). The GNFs transformed to graphene structures and the metallic nanoparticles were encapsulated by the N-F graphene layers.…”

Rationally Designed Zn-Anode and Co3O4-Cathode Nanoelectrocatalysts for an Efficient Zn–Air Battery

“…), and first-row transition metals (e.g., Fe, Zn, etc.). Depending on the nature of the anode, both aqueous and nonaqueous metal–air batteries are extensively persuaded. , Such devices are ultralightweight with a high theoretical energy density (aqueous aluminum–air battery of 8076 Wh kg –1 and nonaqueous Li–air battery of 11429 Wh kg –1 ), which is almost 30 times higher than that of conventional Li-ion batteries (100–265 Wh kg –1 ). , Due to favorable properties, zinc–air (Zn–air) rechargeable batteries have received considerable attention, − although they are less superior to aluminum–air batteries . Presently, Zn–air batteries face many technical challenges that hinder their commercialization because of the issues related to anodes, electrolytes, and air cathodes, some of which are: (1) reaction of metal anode with electrolyte that forms a passivating film, which causes irreversible deterioration of battery performance; (2) corrosion of Zn anode generates heat and hydrogen gas; (3) during charging/discharging, uncontrollable dissolution/deposition of anode material forms dendrites, leading to internal short circuit, device misshape, and occasional battery failure; (4) difficulty in finding stable, less volatile, and less toxic oxygen absorber electrolyte with a wider electrochemical window; and finally (5) low solubility of byproducts and less stability of air cathodes.…”

Interface Engineering and Phase Regulation in CoP/CePO4 Heterostuctures for Boosting Oxygen Evolution Electrocatalysis

“…In consideration of the traditional-fossil-fuel-related energy crisis and environmental pollution, it is urgently required to explore sustainable and clean energy systems. The oxygen evolution reaction (OER) is the critical half reaction within different energy-related electrochemical systems, for example, water splitting, CO 2 reduction reaction, metal–air batteries, etc. − However, the OER involving proton-coupled four-electron transfer pathway is kinetically unfavorable, which requires a large overpotential and needs electrocatalysts to speed up as a consequence. − The state-of-the-art noble Ir- and Ru-based nanomaterials have shown high electrocatalytic activity, but their low reserve and corresponding high cost hinder extensive industrial applications. Therefore, it is highly imperative to explore advanced electroctalysts based on a transition metal as alternative substitutes to promote the overall energy utilization efficiency.…”