A Ternary Ni₄₆Co₄₀Fe₁₄ Nanoalloy‐Based Oxygen Electrocatalyst for Highly Efficient Rechargeable Zinc–Air Batteries

Abstract

Replacing noble-metal-based oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts is the key to developing efficient Zn-air batteries (ZABs). Here, a homogeneous ternary Ni Co Fe nanoalloy with a size distribution of 30-60 nm dispersed in a carbon matrix (denoted as C@NCF-900) as a highly efficient bifunctional electrocatalyst produced via supercritical reaction and subsequent heat treatment at 900 °C is reported. Among all the transition-metal-based electrocatalysts, the C@NCF-900 exhibits the highest ORR performance in terms of half-wave potential (0.93 V) in 0.1 m KOH. Moreover, C@NCF-900 exhibits negligible activity decay after 10 000 voltage cycles with minor reduction (0.006 V). In ZABs, C@NCF-900 outperforms the mixture of Pt/C 20 wt% and IrO , cycled over 100 h under 58% depth of discharge condition. Furthermore, density functional theory (DFT) calculations and in situ X-ray absorption spectroscopy strongly support the active sites and site-selective reaction as a plausible ORR/OER mechanism of C@NCF-900.

Dynamic active-site generation of atomic iridium stabilized on nanoporous metal phosphides for water oxidation

“…12a. The white line intensity of np-Ir/NiFeP is slightly higher than that of np-NiFeP, implying the partial oxidation of the Ni species and the formation of an oxygen-enriched surface which provides the anchoring ligand for the Ir species 8,42 . After the activation process, the absorption-edge of np-Ir/NiFeO shifts to higher energy, in combination with an increase in the white line intensity due to the formation of a Ni (oxy)hydroxide layer 9 .…”

Dynamic electrocatalyst with current-driven oxyhydroxide shell for rechargeable zinc-air battery

“…Previously, limitations in the availability and rechargeability of oxygen electrocatalysts have hindered their popularization, but blooming efforts on exploring suitable and durable candidates to catalyze cathode reactions have led to the recent rejuvenation of this century-old technology [4][5][6] . As such, huge families of materials have been investigated, including metals, alloys, oxides, sulfides, nitrides, phosphides, and their derived composites with carbon 2,[7][8][9][10][11][12][13][14][15][16][17][18] . To this day, exploration for ideal bifunctional electrocatalysts remains to be the research mainstream, but attention is shifting toward understanding the relationship between battery performance and physiochemical properties of electrocatalysts for performance breakthrough.…”

d-Orbital steered active sites through ligand editing on heterometal imidazole frameworks for rechargeable zinc-air battery

“…Platinum on carbon (Pt/C) and ruthenium oxide (RuO 2 ) are the respective ORR and OER benchmarks, however, their applications in rechargeable ZABs are not favored due to their scarcity and inferior bifunctionality 7,13 . Previous attempts on economically viable electrocatalysts primarily involve inorganic candidates, such as heteroatom-doped carbon materials, metal compounds or their composites 9,[14][15][16][17][18][19][20][21][22][23][24] . However, their electrocatalytic activity and stability are limited by dissolution or aggregation of inorganic components triggered by corrosion in highly concentrated alkaline electrolytes of oxygen free radicals emerged during battery cycling 3,25,26 .…”