Two-phase versus two-stage versus multi-phase lithiation kinetics in silicon

We classify the lithiation process into three types, namely, two-phase, two-stage, and multi-phase lithiation. We found that under a given charging rate, smaller electrochemical Biot number of beta will likely to result in two-phase lithiation, while larger beta may lead to multi-phase lithiation. For the film anode, intermediate beta, or intermediate charging rate, will yield two-stage lithiation, and the Li concentration during the first stage of the lithiation is determined by the relationship between beta and the charging rate (or more precisely the Li flux supplied to the Si/LixSi phase interface). Such two-stage lithiation does not occur in the particle or fiber anode. (C) 2013 AIP Publishing LLC.