Structural, magnetic and electrochemical investigation of novel binary Na2-x(Fe1-yMny)P2O7 (0 <= y <= 1) pyrophosphate compounds for rechargeable sodium-ion batteries

Barpanda, Prabeer and Liu, Guandong and Mohamed, Zakiah and Ling, Chris D and Yamada, Atsuo (2014) Structural, magnetic and electrochemical investigation of novel binary Na2-x(Fe1-yMny)P2O7 (0 <= y <= 1) pyrophosphate compounds for rechargeable sodium-ion batteries. In: SOLID STATE IONICS, 268 (B, SI). pp. 305-311.

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Abstract

Pyrophosphate cathodes have been recently reported as a competent family of insertion compounds for sodium-ion batteries. In the current study, we have investigated the binary Na2 - x(Fe1 - yMny)P2O7 (0 <= y <= 1) pyrophosphate family, synthesized by the classical solid-state method. They form a continuous solid solution maintaining triclinic P-1 (#2) symmetry. The local structural coordination differs mainly by different degrees of Na site occupancy and preferential occupation of the Fe2 site by Mn. The structural and magnetic properties of these mixed-metal pyrophosphate phases have been studied. In each case, complete Fe3+/Fe2+ redox activity has been obtained centered at 3 V vs. Na. The Fe3+/Fe2+ redox process involves multiple steps between 2.5 and 3 V owing to Na-cation ordering during electrochemical cycling, which merge to form a broad single Fe3+/Fe2+ redox peak upon progressive Mn-doping. (C) 2014 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Publication:	SOLID STATE IONICS
Publisher:	ELSEVIER SCIENCE BV
Additional Information:	Copyright for this article belongs to the ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Keywords:	Sodium-ion battery; Pyrophosphate; Na2FeP2O7; Na2MnP2O7; Solid-solution
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	14 Feb 2015 13:35
Last Modified:	14 Feb 2015 13:35
URI:	http://eprints.iisc.ac.in/id/eprint/50819

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