Super Charge Separation and High Voltage Phase in NaxMnO2

Published

December 12, 2018

Author(s)

Xi Chen, Yichao Wang, Kamila Wiaderek, Xiahan Sang, Olaf Borkiewicz, Karena Chapman, James LeBeau, Jeffrey W. Lynn, Xin Li

Abstract

Na_xMnO_{2 shows Mn}u3+^ and Mn^⁴⁺ charge separation with charge stripe ordering upon Na de-intercalation at x=5/8, similar to many colossal magnetoresistance materials. We show in this paper that, surprisingly, at lower Na compositions of 5/8 >x less than or equal to}1/18 the phase evolution pathway of Na_xMnO₂ upon Na de-intercalation shows a unique phenomenon of super charge separation, where the Mn³⁺ and Mn^4+^ ions fully charge-separate into charge super-plans rather than stripes. These super-plans dominate both the electronic and magentic interactions in NaMnO₂. Na ions in Mn³⁺ super-plans also naturally pillar the MnO₂ layers to form the unusual O1 phases with large interlayer distances at x < 1/3, contributing to the high capacity.

Citation

Advanced Functional Materials

Volume

28

Issue

50

Pub Type

Journals

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Keywords

Na batteries, Na de-intercalation, full Mn charge separation, Mn super-planes, neutron diffraction, high antiferromagnetic transition

Citation

Chen, X. , Wang, Y. , Wiaderek, K. , Sang, X. , Borkiewicz, O. , Chapman, K. , LeBeau, J. , Lynn, J. and Li, X. (2018), Super Charge Separation and High Voltage Phase in Na_xMnO₂, Advanced Functional Materials, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=926389 (Accessed May 4, 2024)