文摘
Hollow carbon nanospheres (HCNSs) were fabricated by annealing the Cu–C core–shell nanoparticles at 1250 °C in vacuum. The as-obtained HCNSs have ultrathin shell of 1–3 nm in thickness, small size of about 20 nm in diameter, high surface area of 300 m2 g–1, and ultrasmall pores below 5 nm within the C shells. The HCNSs exhibit excellent electrochemical performance as anode materials for lithium-ion batteries. A reversible capacity of 400 mAh g–1 and capacity retention of nearly 100% are achieved at the current density of 186 mA g–1 after 100 charging–discharging cycles. The high reversible capacity, improved high-rate capability, and outstanding cycling stability could be attributed to their unique structural characteristics including the extremely small diameter, the high surface area and the hollow structure with porous, ultrathin shell.