nano-silicon composites, si/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (pedot:pss) and si/c, were prepared by an in situ chemical polymerization of 3,4-ethylenedioxythiophene (edot) with nano-si particles in a pss aqueous solution and subsequent carbonization of si/pedot:pss, respectively. the nano-si particles were embedded in a shapeless pedot: pss matrix and amorphous carbon in the corresponding composite. energy dispersive spectroscopy (eds) and x-ray photoelectron spectroscopy (xps) measurements revealed that 2.66 wt% of the element sulfur was doped in the carbon matrix for si/c composite. both the si/pedot: pss and si/c composite electrodes exhibited higher initial coulombic efficiency and better cycling performance than the bare nano-si anode. the si/c composite showed the best electrochemical performance, retaining a specific capacity of 768 ma h g(-1) and a coloumbic efficiency of 99.2% after 80 cycles, with a very small initial capacity loss of 2.80% and a capacity fade of 0.48% per cycle.