Cu2O-SnO/poly(3,4-ethylenedioxythiophene, PEDOT) nanocomposites (CSPs) were synthesized by polymerizing a mixture consisting of Sn(II) acetate and Cu(II) acetate as metal precursors, EDOT as the monomer, and cerium(IV) sulfate as the oxidant. Three kinds of CSPs (SnO-rich, homo-phase, and Cu2O-rich CSP) with different contents of metal precursors formed the core-shell structures, in which the metal oxides and metals were encapsulated by PEDOT. The homo-phase CSP consisted of low crystalline Cu2O, amorphous SnO, and nanosized Cu within PEDOT, while both the SnO-rich CSP and Cu2O-rich CSP were composed of high crystalline SnO and Cu2O without Cu nanoparticles. The homo-phase CSP showed excellent discharge and charge capacities of 988.38 and 876 mAh g(-1) in the second cycle, representing high reversibility compared to the other two samples. This is caused by (i) the nanostructured formation by low crystalline Cu2O, amorphous SnO, and nanosized Cu, (ii) the increase of electrical conductivity by nanosized Cu, (iii) the buffering role by PEDOT, and (iv) the formation of a fully interconnected pore structure. (C) 2012 Elsevier B.V. All rights reserved.