The extremely large volume variation and poor electronic conductivity of Si anode materials for lithium ion batteries have seriously hampered their performances and practical applications. SiO_x materials are regarded as ideal alternatives to high-capacity Si anode materials for Li-ion batteries, since the generated Li₂O matrix from Li–SiO_x reactions can effectively accommodate the large volume swing of Si. Furthermore, micron-sized particles with much smaller surface area always present higher initial coulombic efficiency and tap density than nanomaterials. Based on the above considerations, SiO_x microparticles with homogeneously-embedded Si nanocrystals and nanopores were fabricated by magnesiothermic reduction in this work and were further modified by high-electronic-conductivity and flexible polyaniline (PANI)–Ag shell. Profiting from these favorable features, the obtained SiO_x–PANI–Ag micron-composites exhibited better cycling performances (with a reversible capacity of 1149 mA h g⁻¹ after 100 cycles), good initial coulombic efficiency and tap density in comparison with SiO_x-based materials in other works. This study promotes us to exploit advanced Si- or Sn-based materials for Li ion batteries and preparing micro/nano complex structures for promising applications.