Mitigation of mechanical degradation in silicon thin-film anodes via delithiation cut-off voltage control

Abstract

Silicon (Si) is a high-capacity anode material for lithium-ion batteries; however, its large volume change during cycling causes severe mechanical degradation. We show that optimizing the delithiation cut-off voltage effectively suppresses interfacial delamination in Si thin-film anodes. By limiting delithiation at 0.6 V, partial Li retention reduces interfacial stress and prevents structural collapse, achieving 92% capacity retention (2200 mAh g⁻¹) after 100 cycles. Cross-sectional analyses confirmed suppressed shrinkage and strong adhesion to the substrate. This simple voltage-control strategy provides a universal and practical route to enhance the durability of Si-based and other alloy-type anodes.