Speaker
Description
There has been renewed interest in solid state sodium-ion batteries (SIBs) as a safe, sustainable and cost-effective alternative system for large scale energy storage applications.[1] This, in turn, has motivated many studies on the development of materials that facilitate high ionic conductivity over multiple charge-discharge cycles. Layered sodium manganates and the NASICON family of compounds are promising candidate sodium electrode and solid-state electrolyte materials respectively. In both cases, it has been shown that the overall performance of these materials for their respective functions is significantly improved through structural modifications, including by hydration or chemical doping.[2-8] However, the characterisation of these materials are typically limited to techniques which only offer a macroscopic picture, such as electrochemical impedance spectroscopy. As such, direct links between conductivity and structure, particularly with reference to the effect of chemical doping on the microscopic properties of materials are rarely investigated.
We have selected candidate materials which have been shown to be amongst the best performing for their purpose and use high resolution diffraction data to solve their average structure. In parallel, we use quasielastic neutron scattering spectroscopy to gain insight into the diffusion mechanisms at an atomic level. We consequently aim to form a fuller picture of the effects that structural modifications have on the ionic conductivity and hence overall performance of these materials.
Palomares, V., et al., Na-ion batteries, recent advances and present challenges to become low cost energy storage systems. Energy & Environmental Science, 2012. 5(3): p. 5884-5901.
Han, M.H., et al., High-Performance P2-Phase Na2/3Mn0.8Fe0.1Ti0.1O2 Cathode Material for Ambient-Temperature Sodium-Ion Batteries. Chemistry of Materials, 2016. 28(1): p. 106-116.
Han, M.H., et al., Moisture exposed layered oxide electrodes as Na-ion battery cathodes. Journal of Materials Chemistry A, 2016. 4(48): p. 18963-18975.
Jolley, A.G., et al., Improving the ionic conductivity of NASICON through aliovalent cation substitution of Na3Zr2Si2PO12. Ionics, 2015. 21(11): p. 3031-3038.
Khakpour, Z., Influence of M: Ce4+, Gd3+ and Yb3+ substituted Na3+xZr2-xMxSi2PO12 solid NASICON electrolytes on sintering, microstructure and conductivity. Electrochimica Acta, 2016. 196(Supplement C): p. 337-347.
Samiee, M., et al., Divalent-doped Na3Zr2Si2PO12 natrium superionic conductor: Improving the ionic conductivity via simultaneously optimizing the phase and chemistry of the primary and secondary phases. Journal of Power Sources, 2017. 347: p. 229-237.
Song, S., et al., A Na(+) Superionic Conductor for Room-Temperature Sodium Batteries. Scientific Reports, 2016. 6: p. 32330.
Nam, K.W., et al., Critical Role of Crystal Water for a Layered Cathode Material in Sodium Ion Batteries. Chemistry of Materials, 2015. 27(10): p. 3721-3725.
| Topic | Advanced Materials |
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