Despite their potential application in lithium-ion battery electrodes, one apparent disadvantage for SnO2-based materials is that the electrodes suffer low coulombic efficiency especially for the initial cycle, which originates from the irreversible conversion of SnO2 to Sn, the formation of solid electrolyte interphase and the other possible side reactions. Here we design a novel nanofiber structure in which SnO2 nanoparticles are well separated and confined by inner porous carbon framework and then hooped by outer carbon shell. The resultant SnO2/voids@C nanofibers electrode displays not only a high reversible capacity of 986 mAh g−1 at 200 mA g−1 after 200 cycles, but also a high initial coulombic efficiency of 73.5%. It has been shown that such a rational design can efficiently reduce the side reactions and promote the reversible conversion of Sn to SnO2 for both half and full cells.