Hollow Carbon-Nanotube/Carbon-Nanofiber Hybrid Anodes for Li-Ion Batteries

By a novel in situ chemical vapor deposition, activated N-doped hollow carbon-nanotube/carbon-nanofiber composites are prepared having a superhigh specific Brunauer–Emmett–Teller (BET) surface area of 1840 m2 g–1 and a total pore volume of 1.21 m3 g–1. As an anode, this material has a reversible capacity of ∼1150 mAh g–1 at 0.1 A g–1 (0.27 C) after 70 cycles. At 8 A g–1 (21.5 C), a capacity of ∼320 mAh g–1 fades less than 20% after 3500 cycles, which makes it a superior anode material for a Li-ion battery .