One-pot instant flame synthesis of strontium-doped lanthanum nickelate perovskite for energy conversion and storage

Abstract

Perovskite structures have great potential to act as multifunctional electrocatalysts with excellent surface chemistry, reactivity, and electrode kinetics for energy storage and conversion. It is a big challenge to fabricate the bulk perovskite material using low-cost and eco-friendly synthetic route along with desirable characteristics, that is, exposed active sites. To address this issue, we synthesized an important model perovskite material, viz. La<inf>1.85</inf>Sr<inf>0.15</inf>NiO<inf>4</inf> (LSNO), using an instantaneous flame synthesis technique. The current synthesis procedure is a rapid and economical technique regarding raw material cost, synthesis duration, and energy consumption, thereby eliminating the usual multi-step processing compared to other reported techniques so far. The synthesized LSNO has been characterized using various physico-chemical techniques such as thermogravimetric analyses (DTA/TG), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), electron microscopy (SEM/TEM), etc. XRD analysis confirmed the formation of a single phase of LSNO after sintering at 900°C for 12 h. In FT-IR spectra, the absorption bands were noticed at 520, 664, and 880 cm−1 corresponding to the La–O, Ni–O, and Sr–O vibrations. The energy dispersive X-ray spectroscopy (EDX) and XPS studies showed the presence of La, Sr, Ni, and O elements which confirm the purity and stoichiometry of LSNO. Here, we report the quick and hassle-free synthesis. LSNO showed excellent oxygen reduction reaction (ORR) activity with an onset potential of 0.88 V versus Reversible Hydrogen Electrode (RHE), which is lower than several existing perovskite-based electrocatalysts. This sample could also be used as supercapacitor material. The galvanostatic charge/discharge test showed stability even at high current densities with a capacity retention of 97.25% even after 500 cycles. The superior ORR activity and electrochemical performance of LSNO provides an impetus for exploring this economical approach toward perovskite-based material synthesis for energy conversion and storage applications. © 2025 The American Ceramic Society.