Story by: Prof. Ein-Eli Yair (Technion – Israel Institute of Technology) and Prof.  Michaelis Alexander (Dresden University of Technology)

An intrinsic challenge of lithium-ion batteries (LIBs) is the interactions of electrolytes with the anode materials. For anodes with favorably low operating potential, a solid-electrolyte interphase (SEI) is being formed during the initial cycles and it provides stability, albeit traded off by a capacity consumption.

GIF Grantees, Prof. Yair Ein-Eli (Technion-Israel Institute of Technology) and Prof. Alexander Michaelis (Dresden University of Technology) investigate the electrochemistry of anode/electrolyte interface in LIBs. Within their collaboration, an advanced artificial SEI layer has been developed and fabricated (by the Technion team) on the surface of individual particles of powdered graphite, serving as the active anode material in LIBs. By using an atomic layer deposition (ALD) method, each individual microparticle has been conformally coated with such an artificial SEI (Art-SEI), possessing similar morphological characteristics to an electrochemically formed, “natural” SEIs’ composition. Despite their morphological similarities the Art-SEI proved to be significantly superior in terms of its’ electrochemical properties. The obtained Art-SEI film demonstrated enhanced cycling performance in Li-ion cells, fabricated and studied by the Dresden team, essentially mitigating the irreversible capacity loss in the initial cycles of Li-ion cell operation.

Over the last years, the cooperative efforts of the two research teams have made several important contributions to a deeper understanding of the mutual relationships between the formation conditions of the Art-SEI layer and the electrochemical behavior at the anode/electrolyte interphase in Li-ion cells. By using novel single particle measurement (SPM) techniques, developed in the Dresden group, the intrinsic properties and charge transfer kinetics of the Art-SEI were studied at a single microparticle level. This method enabled to gain an accurate insight into the interfacial mechanism build-up without influence of any electrode’s matrix effects (porosity, tortuosity, electrode thickness, particle size distribution, etc.) and other components (binder and conductive additives), constituting typical Li-ion anodes.