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arXiv · 2003.05805

Magnetism and Ion Diffusion in Honeycomb Layered Oxide K$_2$Ni$_2$TeO$_6$: First Time Study by Muon Spin Rotation & Neutron Scattering

N. Matsubara·E. Nocerino·O. K. Forslund·A. Zubayer·K. Papadopoulos·D. Andreica·J. Sugiyama·R. Palm·Z. Guguchia·S. P. Cottrell·T. Kamiyama·T. Saito·A. Kalaboukhov·Y. Sassa·T. Masese·M. Månsson
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Abstract

In the quest of finding novel and efficient batteries, a great interest has raised in K-based honeycomb layer oxide materials both for their fundamental properties and potential applications. A key issue in the realization of efficient batteries based on such compounds, is to understand the K-ion diffusion mechanism. However, investigation of potassium-ion (K$^+$) dynamics in materials using magneto-spin properties has so far been challenging, due to its inherently weak nuclear magnetic moment, in contrast to other alkali ions such as lithium and sodium. Spin-polarised muons, having a high gyromagnetic ratio, make the muon spin rotation and relaxation ($μ$+SR) technique ideal for probing ions dynamics in weak magneto-spin moment materials. Here we report the magnetic properties and K+ dynamics in honeycomb layered oxide material of the K$_2$Ni$_2$TeO$_6$ using $μ$+SR measurements. Our low-temperature $μ$+SR results together with, with complementary magnetic susceptibility, find an antiferromagnetic transition at 26 K. Further $μ$+SR studies performed at higher temperatures reveal that potassium ions (K$^+$) become mobile above 250 K and the activation energy for the diffusion process is Ea = 121(13) meV. This is the first time that K+ dynamics in potassium-based battery materials has been measured using $μ$+SR. Finally our results also indicate an interesting possibility that K-ion self diffusion occurs predominantly at the surface of the powder particles. This opens future possibilities for improving ion diffusion and device performance using nano-structuring.

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N. Matsubara, E. Nocerino, O. K. Forslund, A. Zubayer, K. Papadopoulos, D. Andreica, J. Sugiyama, R. Palm, Z. Guguchia, S. P. Cottrell, T. Kamiyama, T. Saito, A. Kalaboukhov, Y. Sassa, T. Masese, M. Månsson. 2020-06-25. Magnetism and Ion Diffusion in Honeycomb Layered Oxide K$_2$Ni$_2$TeO$_6$: First Time Study by Muon Spin Rotation & Neutron Scattering. https://doi.org/10.1038/s41598-020-75251-x

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