Ultrafine Nickel-Nanoparticle-Enabled SiO2 Hierarchical Hollow Spheres for High-Performance Lithium Storage

The high theoretical capacity and natural abundance of SiO2 make it a promising high-capacity anode material for lithium-ion batteries. However, its widespread application is significantly hampered by the intrinsic poor electronic conductivity and drastic volume variation. Herein, a unique hollow structured Ni/SiO2 nanocomposite constructed by ultrafine Ni nanoparticle (approximate to 3 nm) functionalized SiO2 nanosheets is designed. The Ni nanoparticles boost not only the electronic conductivity but also the electrochemical activity of SiO2 effectively. Meanwhile, the hollow cavity provides sufficient free space to accommodate the volume change of SiO2 during repeated lithiation/delithiation; the nanosheet building blocks reduce the diffusion lengths of lithium ions. Due to the synergistic effect between Ni and SiO2, the Ni/SiO2 composite delivers a high reversible capacity of 676 mA h g(-1) at 0.1 A g(-1). At a high current density of 10 A g(-1), a capacity of 337 mA h g(-1) can be retained after 1000 cycles.