Simple Model for the Capacity of Amorphous Silicon-Aluminum-Transition Metal Negative Electrode Materials

This is the authors' abstract. We don't add key points for this paper.

Thin-film libraries of Si - Al - M (M=Cr, Fe, Mn, Ni) negative electrode materials were characterized using combinatorial and high-throughput techniques. Transition metal content had a large effect on capacity, such that alloys with more than ca. 20 – 50 atom % M did not alloy with Li during room temperature or 70 ° C charge-discharge cycling. The 200 mA h ∕ g contour line was used to separate those compositions that readily alloyed with Li from those that did not. This contour line also approximately connects the lowest M content equilibrium crystalline phases. We propose that all Si - Al - M crystalline equilibrium phases are inactive. The capacity of a given composition of Si - Al - M can be approximated, to first order, using only the equilibrium ternary phase diagram. These results could have a large impact on the study of other, more complex, amorphous alloy negative electrode material systems.