Electrocatalytic activity of co-redox center in phosphate-based oxyanionic sodium battery materials

Sharma, L and Lochab, S and Senthilkumar, B and Barpanda, P (2019) Electrocatalytic activity of co-redox center in phosphate-based oxyanionic sodium battery materials. In: 63rd DAE Solid State Physics Symposium 2018, DAE-SSPS 2018, 18 - 22 December 2018, Hisar, Haryana.

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Abstract

Rechargeable metal-air batteries have come up with high theoretical energy density as compared to existing lithium and sodium ion batteries. Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are the two processes, related to water splitting, over which metal-air batteries run. Since both processes are sluggish, hence, they require a catalyst and since the existing precious-metal based catalysts are selective and expensive, there is a need to find a suitable bifunctional catalyst for the same. Motivated by enhanced structural stability imparted by the polyanionic groups along with many reports on electrocatalytic activity of Cobalt phosphate based materials, we tried to look into the electrocatalytic behavior of Na2CoPO4F and Na4Co3(PO4)2P2O7. Both materials were synthesized via solution combustion route resulting in carbon coated and amorphous particles. The ORR/OER properties of the materials were studied in alkaline solution showing bifunctional behavior. An onset potential of 0.854V and 0.771V vs. RHE was observed for Na2CoPO4F and Na4Co3(PO4)2P2O7 with a current density of 5.84mA cm-2 and 3.4mA cm-2 respectively. The onset potential during OER was observed to be 1.591V and 1.596V vs. RHE for Na2CoPO4F and Na4Co3(PO4)2P2O7 respectively. As an application, aqueous Na-air battery was fabricated using Na2CoPO4F as an air-cathode showing good (dis)charge behavior. © 2019 Author(s).

Item Type:	Conference Paper
Publication:	AIP Conference Proceedings
Publisher:	American Institute of Physics Inc.
Additional Information:	The copyright for this article belongs to American Institute of Physics Inc.
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	19 Dec 2022 06:35
Last Modified:	19 Dec 2022 06:35
URI:	https://eprints.iisc.ac.in/id/eprint/78491

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