Cobalt-Silicon Material Libraries Derived from High Throughput Experimentation and Their Application in Lithium Batteries.

Silicon is one of the most promising anode materials in lithium batteries due to its high storage capacity; however, it suffers from extensive volume changes during charge and discharge in a battery cell. Mixtures of silicon with transition metals potentially forming transition metal silicides are under intense investigation as mechanically stable and electronically conductive frameworks with additional silicon in between. The overall capacity for lithium storage in such mixtures in general decreases with increasing transition metal content, and the interpretation of the data in the literature is controversial. In this work, it is shown how approaches toward high-throughput experimentation allow a deeper insight into the details of phase formation in transition metal silicides and thus their impact on the electrochemical performance of silicon-silicide frameworks as electrodes for advanced lithium batteries. Silicides appear to evolve solely in narrow compositional ranges around commensurate ratios of cobalt and silicon, while the observed capacity reduction is attributed to an impeded and finally blocked motion of lithium ions.