Protection of lithium anodes by atomic layer deposition of metal oxides

Group: CoCooN

Promotors: Christophe DetavernierJolien Dendooven

Supervisors: Bo ZhaoFelix Mattelaer

For more information, call 09/264.43.42 or contact one of the persons above (contact details are appearing by clicking on the person's name)

Driven by the search for better batteries, pure lithium is considered as a potential next-generation anode. Lithium is a promising substitute for conventional intercalation anodes (graphite, silicon, etc.) for lithium-ion batteries because it has a high theoretical capacity (3860 mAh/g), a very low potential (-3.04V vs. standard hydrogen electrode) to maximize cell voltage, and low density (0.534 g/cm3) for high specific energy density. However, the extreme reactivity of the lithium surface can induce parasitic reactions with solvents, contamination, and shuttled active species in the electrolyte, reducing the performance of batteries employing lithium metal as anodes. Moreover, during electrochemical cycling the lithium often forms dendrites, which can cause a short-circuit between the electrodes and result in cell failure. One promising solution to these issues is the application of thin protection layers to stabilize the lithium metal surface.

Selected metal oxides can offer high corrosion resistance, outstanding thermal stability, and favourable chemical inertness towards Li. Based on these merits, selected metal oxides are interesting candidates as the protective layer on the surface of lithium metal. Atomic layer deposition (ALD), which is based on self-limiting chemical reactions between gaseous precursors and a solid surface, offers an ideal method for thin film preparation in view of the layer-by-layer growth mode and atom-level control over the thickness.

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In this thesis, you will deposit metal oxide layers directly on Li metal in order to improve the cycle life and power density of lithium metal anodes. The thesis will provide insight in materials deposition, materials characterisation (electron microscopy, spectroscopic ellipsometry, x-ray based characterisation techniques) and electrochemical benchmarking (galvanostatic and potentiostatic methods, impedance spectroscopy).