Speaker
Ms
Tingting SONG
(RMIT University)
Description
Dealloying, used to fabricate nanoporous metals, is a process where less noble components (e.g. Al) in the precursor (e.g. AlCu) are dissolved, leaving the nobler elements (e.g. Cu) to form a nanoporous structure. The three-dimensionally nanoporous Cu is desired in lithium-ion batteries as current collectors, which has a unique advantage in providing large surface area for active materials and can accommodate structural strain during lithiation/delithiation reactions. From the perspective of phase evolution, the phases may evolve from Al-Cu phases (fcc &alpha-Al(Cu), tetragonal Al2Cu, monoclinic AlCu or combination of them) to fcc Cu.
In-situ laboratory X-ray Diffraction (XRD) and ex-situ synchrotron XRD experimentation have been implemented to characterise the dealloying of different Al-Cu precursors in preparing fcc Cu. Experiments were carried out using Al75Cu25 (&alpha-Al(Cu) and Al2Cu) and Al65Cu35 (Al2Cu and AlCu) alloys. In the case of in-situ lab XRD experimentation, results showed that for Al75Cu25, the disappearance of &alpha-Al(Cu) and Al2Cu, and the formation of Cu began simultaneously, while for Al65Cu35, the dealloying of Al2Cu and AlCu happened in sequence with the formation of Cu. The highly resoluted ex-situ synchrotron results not only confirmed lab XRD observations, but also showed transient phases during dealloying for the first time. This study is a model example to investigate the underlying dealloying mechanism from the perspective of phase evolution, and can provide guidance for the development of nanoporous Cu current collectors for batteries.
| Keywords or phrases (comma separated) | Dealloying, Nanoporous metals, In-situ phase evolution, Transient phases |
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Primary author
Ms
Tingting SONG
(RMIT University)
Co-authors
Dr
Justin Kimpton
(Australian Synchrotron)
Dr
Ming YAN
(RMIT University)
Dr
Nathan Webster
(CSIRO)
Prof.
Qian Ma
(RMIT University)
