Hollow core-shell structured porous Si-C nanocomposites with void space up to tens of nanometres are designed to accommodate the volume expansion during lithiation for high-performance Li-ion battery anodes. An initial capacity of ∼760 mA h g -1 after formation cycles (based on the entire electrode weight) with ∼86% capacity retention over 100 cycles is achieved at a current density of 1 A g -1. Good rate performance is also demonstrated. © 2012 The Royal Society of Chemistry.