HDR Scholarship - Developing new electrodes

Dr Minkyung Kang

Prof Maria Forsyth

Prof Patrick Howlett

Institute for Frontier Materials

Melbourne Burwood Campus

This project is focused on developing new and stable electrodes for next-generation high-energy batteries: anode-free sodium metal batteries (AF-SMBs). Although AF-SMBs can theoretically achieve specific capacity values that are up to ~10× higher than conventional lithium-ion batteries (LIBs), in practice this configuration is plagued by issues associated with metal “dendrite growth”. During battery cycling, repetitive electro-plating/stripping results in the progressive growth of metal dendrites, leading to poor cycle life and safety issues due to short circuiting. Dendrite growth in batteries is rather complex, due to chemical and electrochemical formation/aging of a surface film—the solid electrolyte interphase (SEI)—at the electrode/electrolyte interface during cycling. As this is a complex problem, covering multiple length- and time-scales, an innovative multiscale approach is needed to understand and address it. Scanning electrochemical cell microscopy (SECCM) is capable of high-throughput, synchronous electrochemical and topographical imaging of complex interfaces across length-(sub-nm to mm) and time-scales (sub-ms to days) and will be used in this project to unveil local battery electrode performance directly and unambiguously.

Initially, direct correlation of battery electrode surface structure with Na-deposit morphology (e.g. dendrite growth rate) will be investigated (Year 1) in selected high-safety ionic liquid electrolytes (ILEs). Surface heterogeneity on polycrystalline Cu (poly-Cu, i.e. the negative electrode current collector in AF-SMBs) strongly influences both SEI formation and the interfacial energy between Na and Cu, causing the formation of non-uniform surface films and uneven Na metal growth. Through SECCM, early-stage SEI formation and Na metal nucleation/growth on poly-Cu will be probed, which will then be correlated to surface structure through identical-location microscopic/spectroscopic characterisation (SEM, EBSD, and AFM), unambiguously revealing structure-reactivity at the (sub)nanoscale.

After developing a thorough mechanistic understanding of the initial stages, the ‘multiscale’ aspect of this project will be explored (achieved by changing the dimensions of the SECCM probe and timescale of the measurement) to study the time-evolution of the SEI, and the later stages of Na growth in ILEs. The empirical results will be supported by computational simulations (e.g. DFT, MD and FEM), carried out by collaborators at IFM to further advance a mechanistic understanding (Year 2-3). The results will guide the development of electrode architectures and surface treatments (e.g., using 2D nanomaterials such Boron Nitride nanotubes, in collaboration with IFM researchers) that enable uniform SEIs and growth of contiguous Na films.

This project advances fundamental knowledge and investigative techniques for the study of interfacial phenomena, highly relevant for the development of promising post LIB technologies. Coupling SECCM with identical-location surface characterisation, as well as complementary computational simulations, will provide a clear picture of battery electrode structure-composition-activity relationships. The ultimate outcome will be to provide blueprints for novel low-cost materials for energy conversion and storage applications, in order to shift to new/secure sources of energy supply, as well as mitigate climate change, which are parallel goals within IFM.

Applications will remain open until a candidate has been appointed

This scholarship is available over 3 years.

• Stipend of $28,900 per annum tax exempt (2022 rate)
• Relocation allowance of $500-1500 (for single to family) for students moving from interstate
• International students only:  Tuition fees offset for the duration of 4 years. Single Overseas Student Health Cover policy for the duration of the student visa.

To be eligible you must:

• be either a domestic or international candidate currently residing in Australia. Domestic includes candidates with Australian Citizenship, Australian Permanent Residency or New Zealand Citizenship.
• meet Deakin's PhD entry requirements
• be enrolling full time and hold an honours degree (first class) or an equivalent standard master's degree with a substantial research component.

Please refer to the research degree entry pathways page for further information.

For more information about this scholarship, please contact Dr Minkyung Kang

Dr Minkyung Kang
Email Dr Minkyung Kang
+61 3 924 68968