Please use this identifier to cite or link to this item: https://apo.ansto.gov.au/dspace/handle/10238/11054
Title: Alkali metal-modified P2 NaxMnO2: crystal structure and application in sodium-ion batteries
Authors: Sehrawat, D
Rawal, A
Cheong, S
Avdeev, M
Ling, CD
Kimpton, JA
Sharma, N
Keywords: Electrodes
Crystal lattices
Transition elements
Alkali metals
Transmission electron microscopy
X-ray diffraction
Electric batteries
Issue Date: 18-Aug-2020
Publisher: American Chemical Society
Citation: Sehrawat, D., Rawal, A., Cheong, S., Avdeev, M., Ling, C. D., Kimpton, J. A., & Sharma, N. (2020). Alkali metal-modified P2 NaxMnO2: crystal structure and application in sodium-ion batteries. Inorganic Chemistry, 59(17), 12143-12155. doi:10.1021/acs.inorgchem.0c01078
Abstract: Sodium-ion batteries (NIBs) are an emerging alternative to lithium-ion batteries because of the abundance of sodium resources and their potentially lower cost. Here we report the Na0.7MnO2 solid state synthesized at 1000 °C that shows two distinct phases; one adopts hexagonal P2-type P63/mmc space group symmetry, and the other adopts orthorhombic Pbma space group symmetry. The phase ratio of P2 to the orthorhombic phase is 55.0(5):45.0(4). A single-phase P2 structure is found to form at 1000 °C after modification with alkali metals Rb and Cs, while the K-modified form produces an additional minor impurity. The modification is the addition of the alkali elements during synthesis that do not appear to be doped into the crystal structure. As a cathode for NIBs, parent Na0.7MnO2 shows a second charge/discharge capacity of 143/134 mAh g–1, K-modified Na0.7MnO2 a capacity of 184/178 mAh g–1, Rb-modified Na0.9MnO2 a capacity of 159/150 mAh g–1, and Cs-modified Na0.7MnO2 a capacity of 171/163 mAh g–1 between 1.5 and 4.2 V at a current density of 15 mA g–1. The parent Na0.7MnO2 is compared with alkali metal (K, Rb, and Cs)-modified NaxMnO2 in terms of surface morphology using scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy, scanning electron microscopy, 23Na solid-state nuclear magnetic resonance, and X-ray photoelectron spectroscopy and in terms of electrochemical performance and structural electrochemical evolution using in situ or operando synchrotron X-ray diffraction. © 2020 American Chemical Society
URI: https://doi.org/10.1021/acs.inorgchem.0c01078
https://apo.ansto.gov.au/dspace/handle/10238/11054
ISSN: 1520-510X
Appears in Collections:Journal Articles

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