Superdurable Bifunctional Oxygen Electrocatalyst for High-Performance Zinc–Air Batteries

Abstract

The development of high-efficiency and durable bifunctional electrocatalysts for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critical for the widespread application of rechargeable zinc–air (Zn–air) batteries. This calls for rational screening of targeted ORR/OER components and precise control of their atomic and electronic structures to produce synergistic effects. Here, we report a Mn-doped RuO2 (Mn-RuO2) bimetallic oxide with atomic-scale dispersion of Mn atoms into the RuO2 lattice, which exhibits remarkable activity and super durability for both the ORR and OER, with a very low potential difference (ΔE) of 0.64 V between the half-wave potential of ORR (E 1/2) and the OER potential at 10 mA cm–2 (E j10) and a negligible decay of E 1/2 and E j10 after 250 000 and 30 000 CV cycles for ORR and OER, respectively. Moreover, Zn–air batteries using the Mn-RuO2 catalysts exhibit a high power density of 181 mW cm–2, low charge/discharge voltage gaps of 0.69/0.96/1.38 V, and ultralong lifespans of 15 000/2800/1800 cycles (corresponding to 2500/467/300 h operation time) at a current density of 10/50/100 mA cm–2, respectively. Theoretical calculations reveal that the excellent performances of Mn-RuO2 is mainly due to the precise optimization of valence state and d-band center for appropriate adsorption energy of the oxygenated intermediates.

Constructing atomically-dispersed Mn on ZIF-derived nitrogen-doped carbon for boosting oxygen reduction

“…Manganese (Mn) adjacent to Fe on the periodic table has the outer layer electrons of 3d 5 4s 2 . The adsorption energy of Mn-N-C for *OH is lower than that of Fe-N-C, which is consistent with the density functional theory (DFT) analyses ( Xiong et al, 2019 ; Hu et al, 2021 ; Li et al, 2021 ; Peng et al, 2021 ; Zhou et al, 2022 ). Besides, Mn is among the richest metals on earth.…”

Tensile‐Strained RuO2 Loaded on Antimony‐Tin Oxide by Fast Quenching for Proton‐Exchange Membrane Water Electrolyzer

“…Similar morphology has been reported in Co‐doped RuO 2 . [ 10a ] Furthermore, elementals mapping images (Figure 1d ) show that Ru elements are more prone to distribute on the outside while Sn elements are on the inside, proving that the nanorods outside are RuO 2 crystals instead of ATO. The nanorod structures of s ‐RuO 2 /ATO can favor the maximum exposure of OER active sites.…”

“…Here, it should be noted that small fractions of Co residuals are inevitable due to Co‐HMT precursors. Since several reports have clarified that Co dopants positively influence the OER, [ 10 , 21 ] we have tentatively kept the Ru/Co ratios during the substitution processes for a rational comparison.…”

“…In previous reports, doping of foreign atoms is the mainstream for boosting the OER activity of RuO 2 . [ 10 ] Indeed, Sargent et al. had done high‐throughput density functional theory (DFT) screenings and experimental trials to indicate that the Ru‐Ir‐Sr ternary oxide can achieve exceptionally high OER activity and stability.…”

Metal–Organic Frameworks (MOFs) Derived Materials Used in Zn–Air Battery

“…However, the kinetics of the multi-electron transfer process of OER and ORR the sluggish O 2 reduction kinetics. Currently, Pt-based catalytic particles exhibit the best catalytic performance for ORR [ 14 ] and either IrO 2 or RuO 2 for OER [ 15 , 16 ], but these rare and expensive noble metal nanomaterials can only selectively catalyze ORR or OER with poor long-term stability single function. Thus, the rational design of rich resources, high efficiency, and durability of non-noble metal bifunctional electrocatalysts is the key to improve the kinetics of ORR and OER reactions and accelerate the commercial application of Zn–air battery [ 17 , 18 , 19 ].…”