Double-Activator Modulation of Ultrahigh Surface Areas on Doped Carbon Catalysts Boosts the Primary Zn–Air Battery Performance

Abstract

The exploration of high-performance and low-cost carbon-based catalysts as an excellent substitute for Pt-based catalysts for the oxygen reduction reaction (ORR) is key to solve the commercialization of metal−air batteries. Herein, we report an efficient strategy to design a porous-rich N, F-codoped carbon-based ORR catalyst (A-NFCF-950) by double-activator (ZnCl 2 , NH 4 F) modulation of the specific surface area and pore structure. Among them, ZnCl 2 as a pore modifier can help to produce an ultrahigh specific surface area (up to 2251 m 2 g −1 ) and also facilitate the exposure of more doping active sites. Furthermore, the NH 4 F modifier can be convenient for the charge density regulation of adjoining carbon atoms, which further significantly promotes the graphitization degree and accelerates oxygen dissociation at the catalyst. The electrochemical results indicate that the ORR activity and cycling stability of A-NFCF-950 are comparable to those of the Pt/C catalyst in a 0.1 M KOH electrolyte. In addition, the assembled Zn−air battery using A-NFCF-950 shows a higher power density (220 mW cm −2 ) and a larger capacity energy density (872 Wh kg −1 Zn). This work opens a way to synthesize doped carbon materials with ultrahigh surface areas serving for conventional Pt-based materials toward the ORR in metal−air batteries.

Ultrahigh-Loaded Fe Single Atoms and Fe3C Nanoparticle Catalysts as Air Cathodes for High-Performance Zn–Air Batteries

“…The diffraction peaks of Fe 3 C-FeSA@3DCN at around 45° were consistent with the standard diffraction peaks of Fe 3 C (PDF#85-1317), indicating that Fe and C doped in the material combined to form Fe 3 C nanoparticles. The (101) lattice plane of graphitic carbon in amorphous carbon was formed in NC@CNTs without Fe doping at around 43°, which is consistent with the formation of NCs . The Raman spectra of Fe 3 C-FeSA@3DCN, NC@3DCN, and NC are shown in Figure b, and the disorder degree and defect density of the material could be obtained by analyzing the ratio of I D and I G .…”

“…The (101) lattice plane of graphitic carbon in amorphous carbon was formed in NC@CNTs without Fe doping at around 43°, which is consistent with the formation of NCs. 38 The Raman spectra of Fe 3 C-FeSA@3DCN, NC@3DCN, and NC are shown in Figure 3b, and the disorder degree and defect density of the material could be obtained by analyzing the ratio of I D and I G . All samples show two typical peaks at 1350 and 1580 cm −1 , which are assigned to the D and G bands of carbon, respectively.…”

3D Hierarchical Porous Carbon Aerogel Electrocatalysts Based on Cellulose/Aramid Nanofibers and Application in High-Performance Zn–Air Batteries

“…As a self-sacrificial template, the volatilization of excess Cd at a moderate pyrolysis temperature favors the formation of a microporous structure. 46 During the pyrolysis process, some volatile substances were released from the TOCNF and ANF, resulting in cross-linked carbon nanofibers with a porous morphology that ensures efficient ion diffusion and proton transfer during the catalytic reaction. Simultaneously, the inherent nitrogen in ANF was partially doped into the carbon lattice, and some defects could be incorporated into the carbon skeleton, including surface defects and hole defects.…”

“…The freeze-dried aerogels were carbonized at 800 °C under an Ar atmosphere to obtain N/CA x -Cd ( x represents the mass ratio of ANF in the aerogel precursor). As a self-sacrificial template, the volatilization of excess Cd at a moderate pyrolysis temperature favors the formation of a microporous structure . During the pyrolysis process, some volatile substances were released from the TOCNF and ANF, resulting in cross-linked carbon nanofibers with a porous morphology that ensures efficient ion diffusion and proton transfer during the catalytic reaction.…”

“…With the accelerating dissipation of fossil fuels and a range of emerging environmental concerns, unprecedented and enormous market demands have stimulated the exploitation of sustainable energy sources and storage technologies. − The intrinsically sluggish oxygen reduction reaction (ORR) remains a pivotal and decisive process in electrochemical energy conversion technologies including fuel cells and metal–air batteries. − Platinum-based noble-metal electrocatalysts are often used to accelerate the kinetic process of ORR, but their high cost and dramatic deterioration during long-term operations inevitably hinder their large-scale commercial applications in these sustainable energy technologies. − Carbon-based materials are deemed promising alternatives to platinum-based electrocatalysts owing to their low cost, excellent electrical conductivity, and large specific surface area (SSA), which have aroused appreciable attention. − …”