In situ cycling and mechanical testing of silicon nanowire anodes for lithium-ion battery applications

In this work, we investigate the mechanical properties of silicon nanowires, which have been subjected to in situ electrochemical alloying and de-alloying with lithium inside a scanning electron microscope (SEM). Following de-alloying, in situ tensile testing of wires was performed inside a SEM using a microelectromechanical force sensor and a piezo-driven actuator. Compared to pristine silicon nanowires, the de-alloyed wires show a significant decrease in both their elastic modulus as well as in their ultimate tensile strength with indications that the newly formed amorphous silicon layer changes the mechanical properties of the wire.