Due to its high theoretical capacity and its natural abundance, silicon (Si) has attracted much attention as a promising Li-ion anode material.  However, progress towards a commercially viable Si anode has been impeded by Si's rapid capacity fade and low Coulombic efficiency, especially for the first cycle. New conformal nanoscale coatings via atomic layer deposition (ALD)/molecular layer deposition (MLD) are being developed to accommodate the volumetric expansion, protect the surface from the reactive electrolytes, as well as ensure the electronic paths through the composite electrodes. Successfully coated Si anodes have exhibited greatly improved cycling performance than that of uncoated Si anodes. The results show that 10 nm aluminium alkoxide coatings can enable the durable cycling of Si anodes over a hundred cycles without major capacity fade.  High-resolution microscopy was performed to study the effect of the conformal coatings on the evolution of Si structure and morphology during lithiation/delithaition. The findings imply that the good resilience of the Alucone coatings provides sufficient mechanical support to accommodate the major volumetric changes experienced by Si anodes, as well as to aid in the recovery and preservation of the whole composite network upon delithiation. In-situ optical spectroscopy was also applied to understand the impact of coating materials on the interfacial chemistry of Si anodes. These results will be presented in detail.

Understand the effect of conformal coatings on electrochemical performance and interfacial chemistry of Si anodes

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.