SiO_x@ZrO₂@C Nanospheres as a High-Capacity and Stable Anode Material for Lithium-Ion Batteries

Silicon oxide (SiO_x) has been widely studied due to its ultrahigh theoretical specific capacity for lithium storage. However, its inherent low electronic conductivity and large volume change before and after lithium insertion have limited its commercialization. To address this issue, we report the synthesis of SiO_x@ZrO₂@C ternary composite nanospheres by convenient and scalable wet chemistry and sintering processes. In the unique structure of 3D porous SiO_x@ZrO₂@C nanospheres, zirconium oxide (ZrO₂) supplies high structural stability, while the amorphous carbon (C) layer helps to form a stable solid–electrolyte interface, suppress volume expansion, and greatly improve the conductivity. Electrochemical measurements demonstrate that the SiO_x@ZrO₂@C nanospheres exhibit a capacity retention of 72.2% after 500 cycles at 500 mA g^–1. At a high current density of 800 mA g^–1, the SiO_x@ZrO₂@C nanospheres can still deliver a capacity of 529.1 mAh g^–1. This work provides a promising mass-scale synthesis method for producing SiO_x composites and introduces a high-performance anode material for lithium-ion batteries.