We have successfully synthesized NixSnyOz nanostructured composites consisting of Sn, SnO, Ni3Sn, and Ni3Sn2 phases via galvanic replacement reaction between Ni2+ and Sn at high temperature in triethylene glycol medium. The composites are used as novel anode materials for lithium-ion batteries. At different reaction times, the as-prepared composites show hollow structures with different compositions and particle sizes, as analyzed by X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. For example, the NixSnyOz-6h composite electrode with a small particle size (<60 nm) exhibits highly stable specific capacities of 615 and 555 mAh g−1 at current densities of 100 and 1000 mA g−1 after 100 cycles, respectively, and a high rate performance with a high reversible capacity of 377 mAh g−1 at a current density of 3000 mA g−1. The excellent electrochemical performance can be attributed to the large contact area between the electrolyte and the material as well as to the mixed inactive phases of Ni and Li2O combining with the hollow structures, which could act as an electron conductor and an effective buffer against volume changes during cycling and could inhibit the agglomeration of active particles (Sn), resulting in a stable-structure active material and accelerated kinetics of the reaction.