Abstract:
Rechargeable Zinc-air batteries (RZABs) have gained significant recognition in
renewable energy due to their exceptional safety, cost- effectiveness, enhanced energy
density (1084 Wh·kg⁻¹), and environmental sustainability. The sluggish rate of oxygen
electrolysis requires noble metal-based electrocatalysts for Re-zinc-air batteries
(RZABs), but these are expensive and exhibit instability issues. This requires the
development of efficient, highly stable, and economical non-noble metal dual functional electrocatalysts for oxygen evolution (OER) and oxygen reduction (ORR)
reactions. We introduce an easy strategy to synthesize trimetallic nitrogen-containing
nanoporous carbon (FeMnCo/N-C) electrocatalyst. By combining Fe/Mn-MOF with
ZIF-67, followed by pyrolysis, we obtain FeMnCo/N-C. The prepared materials are
characterized by using XRD for phase confirmation, SEM for studying the
morphology and surface properties. Raman spectroscopy was utilized for
identification of functional groups. The electrochemical techniques like cyclic
voltammetry, Linear Sweep Voltammetry and Electrochemical Impedance
Spectroscopy were utilized to test the electrochemical performance of the material.
FeMnCo/N-C an electrocatalyst, featuring a high surface area, reveals exceptional
bifunctional activity, with potential at 10 mA/cm2
(Ej (10) = 1.60 V) for the oxygen
evolution reaction (OER) and half-wave potential (E1/2 = 0.83 V) for the oxygen
reduction reaction (ORR), which results in a potential gap of 0.77 V, exceeding
Fe/Mn-C and Co/N-C. A zinc-air battery containing FeMnCo/N-C electrocatalyst has
exhibited specific capacity of 721.7 mAh/g , Power density of 87.2 mW/cm2
and stable charge- discharge 60 cycles in 3.8 hrs. The bifunctional activity of an
electrocatalyst is due to the combined effects of the tri-metals, nitrogen-doped carbon,
and their porous nature, offering FeMnCo/N-C a notable candidate for wider
application in electrochemical energy devices.
