Browsing by Author "Cheung, E"

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    4-phenoxyphenol: a porous molecular material
    (American Chemical Society, 2012-04-01) Thomas, LH; Cheung, E; Jones, AOF; Kallay, AA; Lemée-Cailleau, MH; McIntyre, GJ; Wilson, CC
    4-Phenoxyphenol is a simple organic molecule that crystallizes as a porous material with channels running throughout the structure. The channels are constructed by a 6-fold hydrogen bonded ring and can host solvent molecules incorporated during crystal growth, with a minimum channel diameter of 5.8-5.9 angstrom; each channel usually contains a single solvent molecule per unit cell. The hydrogen bonded ring shows surprising flexibility, being able both to breathe and to sustain its crystalline integrity even when grown with empty pores. This is particularly surprising given that the remainder of the interactions within the crystal structure are C-H center dot center dot center dot pi interactions and are weak in nature. It is also possible to grow "dry" porous 4-phenoxyphenol crystals by using a bulky solvent in the recrystallization. © 2012, American Chemical Society.
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    Solid ionic conductors for energy applications: developing a complete picture from structure and dynamics
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2018-11-19) Cheung, E; de Souza, NR; Sharma, N
    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 Page 3 ANBUG-AINSE Neutron Scattering Symposium, AANSS 2018 / Book of Abstracts 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. © The Authors.