Origami Silicon Anodes: Geometric Design for Structural Elasticity and Connectivity.

Achieving stable cycling of high-capacity battery electrodes with large volume changes remains a significant challenge, with their mechanical failure and sluggish kinetics, primarily due to inadequate structural accommodation and inefficient transport pathways. Here, a magnesiothermic crystallization approach is presented to construct origami capsule (OC) architectures, imparting flexibility and conformability to inherently brittle silicon, featuring highly interconnected 2D silicon nanosheets (2.5 nm thickness) with built-in nanopores encapsulated within a pressure-tolerant conformal microshell. The design leverages geometric features at both the nanoscale (within nanosheets) and microscale (capsule assembly) to impart structural elasticity and connectivity for efficient stress dissipation, enhancing mechanical integrity and rapid transport kinetics. Consequently, the OC anode exhibits low electrode swelling (14.7%) at 2945 mAh g and exceptional rate capability, delivering a high capacity and ≈100% retention after 470 cycles at a large current density of 6 A g. This work bridges geometric design and materials science, opening new avenues for high-performance energy storage solutions.