Green Synthesis of Dual Carbon Conductive Network-Encapsulated Hollow SiO _x Spheres for Superior Lithium-Ion Batteries

Designing hollow/porous structure is regarded as an effective approach to address the dramatic volumetric variation issue for Si-based anode materials in Li-ion batteries (LIBs). Pioneer studies mainly focused on acid/alkali etching to create hollow/porous structures, which are, however, highly corrosive and may lead to a complicated synthetic process. In this paper, a dual carbon conductive network-encapsulated hollow SiO _x (DC-HSiO _x) is fabricated through a green route, where polyacrylic acid is adopted as an eco-friendly soft template. Low electrical resistance and integrated electrode structure can be maintained during cycles because of the dual carbon conductive networks distributed both on the surface of single particles formed by amorphous carbon and among particles constructed by reduced graphene oxide. Importantly, the hollow space is reserved within SiO _x spheres to accommodate the huge volumetric variation and shorten the transport pathway of Li⁺ ions. As a result, the DC-HSiO _x composite delivers a large reversible capacity of 1113 mA h g^-1 at 0.1 A g^-1, an excellent cycling performance up to 300 cycles with a capacity retention of 92.5% at 0.5 A g^-1, and a good rate capability. Furthermore, the DC-HSiO _x//LiNi_0.8Co_0.1Mn_0.1O₂ full cell exhibits high energy density (419 W h kg^-1) and superior cycling performance. These results render an opportunity for the unique DC-HSiO _x composite as a potential anode material for use in high-performance LIBs.