Stable lithium storage enabled by a 3D core-shell Cu/Si integrated anode.

Silicon anodes face challenges in lithium storage, primarily due to severe volume expansion (∼300%). Here we develop an integrated core-shell Cu/Si electrode by first growing CuO arrays on Cu mesh, followed by simultaneous silicon deposition and CuO reduction via low-pressure chemical vapor deposition (LPCVD). The resulting Cu framework functions dually as a current collector and a buffering network. As a result, this binder-free Cu/Si electrode delivers an ultrahigh reversible capacity of 3450 mAh g-1 at 0.5 A g-1 with an initial Coulombic efficiency of 85%, maintains 2000 mAh g-1 at 5 A g-1, and 76.8% capacity retainion after 400 cycles at 1 A g-1. The exceptional performance stems from its integrated architecture, which ensures robust structural integrity during cycling.