Constructing novel SiOx hybridization materials by a double-layer interface engineering for high-performance lithium-ion batteries

SiOx-based anode materials (0 < x < 2) have been regarded as an appealing candidate for anode material of commercial Lithium-ion batteries accounting for their ultrahigh theoretical capacity and low cost. However, its large-scale applications have been hampered by the serious volume expansion during repeated cycles, low intrinsic conductivity and unsatisfactory initial Coulombic efficiencies. Herein, to address these inherent de-ficiencies, a hierarchical SiOx-based anode with double-layer coatings of Sn inner layer and N-doped carbon outer shell is elaborately designed by a facile two-step hydrolysis process and polymer coating technology. Benefiting from the "synergistic effect" between Sn and SiOx at different working potentials and a well-designed double-layer coating structure, the resultant SiOx/C@Sn@NC anode displays excellent electrochemical proper-ties, including an enhanced initial Coulomb efficiency (73.3%) efficiency, higher reversible capacity (991 mAh g-1) and superior long lifespan. Moreover, comprehensive characterization based on the reaction kinetics and structural stability proved that such enhanced ICE and cycling stability of anode material stem from its unique double-layer coating structure and multiple active components, which can significantly improve the diffusion of ion and charge transport, stabilize solid-electrolyte interphase (SEI) layer and absorb the expansion stress of electrode. Therefore, this study provides an efficient and feasible strategy to overcome the limitations of high-capacity SiOx-based anode materials via hybridization design with various active components and a double-layer coating strategy.