The Planar Architecture of Silicon Anode Enables Stress Relief in Stable Lithium-Ion Batteries

Silicon is a promising anode for lithium-ion batteries but suffers tremendous volume change during cycling. Scalable and low-cost fabrication of silicon anodes with minimized internal stress, avoiding electrode degradation and capacity decline, remains a significant challenge. Herein, a planar silicon demonstrates internal stress release in the electrode at electrochemical cycling, which indicates a favorable areal capacity of 3.4 mAh cm^-2 and a stable specific capacity of 810 mAh g^-1 even after 600 cycles at a remarkable current density of 3.6 A g^-1. Such good results are mainly ascribed to the planar structure that changes the expansion direction, which enables stress relief in the electrode. In addition, the planar structure provides abundant contact area, which aligns the anode stack and then shortens the ion diffusion. This work demonstrates useful insights on stress release through structure engineering and revolutionizes the traditional design for lithium-ion batteries, ensuring energy storage devices transcend current limitations.