Electrochemical Evaluation of LaNiO3-Based Perovskites As Bifunctional Cathode Material for Rechargeable Metal-Air Batteries
Authors: Velraj Samgopiraj , Zhu Jiahong , Salazar-Gastelum Moises Israel , Corona Sandoval Erick , Beltrán-Gastélum Mara , Pérez-Sicairos Sergio , Félix-Navarro Rosa María 
Published: February 2020

Rechargeable metal-air batteries with its high energy storage capacity and environment-friendly materials provide one of the most promising solutions as safer energy storage devices [1]. However, the air cathodes of rechargeable metal-air batteries have the issue of irreversibility of the oxygen evolution and reduction reactions [2]. Noble metals have good bifunctional catalytic ability but are not economical sustainable. Among the non-noble catalysts of interest, perovskites with the chemical formula of ABO3have been studied extensively and have recently received increasing attention, due to their higher electrochemical performance and lifetime in the alkaline electrolyte [3,4].

The LaNiO3 perovskite has attracted enormous interest as a substitute of carbon in bifunctional electrodes due to its metal-like conductivity and decent electrochemical activity [5,6]. Although, LaNiO3 is a good oxygen evolution reaction (OER) catalyst with lower oxygen reduction reaction (ORR) capability, a study by Yuasa et al. showed that electrodes prepared using a composite of LaNiO3/LaMnO3 had remarkable bifunctional electrochemical performance due to the good ORR ability of LaMnO3 [5]. Moreover, a LaNi0.9Mn0.1O3 (LaNiO3 with 10% Mn doping) electrode from the same study displayed excellent bifunctional ORR/OER activity showing the potential for doping using other element in LaNiO3. A detailed mechanistic study of different elemental doping and their effect on actual electrode performance in real life conditions has not been previously studied.

In this study, a mechanistic study of the catalytic ability of different doping element on LaNiO3 such as LaNi0.9Mn0.1O3, LaNi0.9Co0.1O3, and LaNi0.9Fe0.1O3will be studied using RDE and RRDE. In addition, air electrodes prepared with these catalysts material will be evaluated for electrochemical performance and stability under real-life experimental conditions.

The XRD of the LaNiO3 perovskite doped with 10 wt.% Mn/Co which were synthesized using the glycine nitrate method are shown in Fig. 1a while, a typical microstructure of these catalyst are shown in Fig.1b. The polarization curves for the electrodes prepared using carbon-free LaNi0.9Mn0.1O3catalyst powder as well as the carbon (Vulcan XC 72R) support are shown in Fig. 2. The electrodes prepared with the perovskites showed exceptional anodic (OER) capabilities compared to carbon electrode. However, the carbon-based electrode had slightly better ORR capabilities. A mechanistic study using RDE/RRDE will provide a better understanding of the intrinsic catalytic ability of the perovskite catalysts and their synergic effect with the carbon support.

References

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[4] G. Che, B.B. Lakshmi, E.R. Fisher, C.R. Martin, Nature, 393, 346 (1998)

[5] M. Yuasa, M. Nishida, T. Kida, N. Yamazoe, and K. Shimanoe, J. Electrochem. Soc., 158, A605 (2011)

[6] G. Karlsson, Electrochimica Acta, 30, 1555 (1985)

Figure 1