Ratcheting of silicon island electrodes on substrate due to cyclic intercalation

Analytical and numerical calculations are conducted to demonstrate a ratcheting mechanism of irreversible and accumulative deformation in patterned Si islands on substrates during lithiation/delithiation cycling. It is shown that ratcheting occurs as soon as one allows the yield stress of Si and/or the friction strength of the interface to vary from lithiation to delithiation half-cycles, and that this important failure mode can be avoided by simply reducing the lateral size of the islands below a critical length scale. The present study provides a feasible explanation for the experimentally observed ratcheting in fractured Si films on substrates.