Porous silicon particles embedded in N-doped graphene and carbon nanotube framework for high-performance lithium-ion batteries

Silicon holds great promise as an anode material for high energy density lithium-ion batteries (LIBs). Despite its extremely high theoretical capacity, challenge with severe capacity fading remains to be overcome. In this study, a rational strategy for trapping porous silicon (PSi) within a highly stable 3D framework constructed with interconnected N-doped graphene (NG) and carbon nanotubes (CNTs) to form a novel composite of [email protected]/CNT via a modified magnesiothermic reduction method is developed for alleviating the large volume expansion and particle fracture and improve electronic conductivity. More importantly, for the first time, the vacancy defects in the trapped PSi within the 3D framework are analyzed. When explored as an anode, the as-developed [email protected]/CNT exhibits excellent lithium storage properties with high specific capacity, remarkable rate capability (850 mAh g−1 at 5 A g−1), good cycling retention of 79.7% over 200 cycles, and consistently high columbic efficiency at a current density of 0.2 A g−1. This work provides new insights into the rational design of electroactive materials with ultrahigh stability and paves the way toward practical applications of silicon-based anodes for high energy density lithium-ion batteries.