Controllable Preparation to Boost High Performance of Nanotubular SiO2@C as Anode Materials for Lithium-Ion Batteries

Due to poor electrical conductivity and significant volume change during the lithiation/delithiation process, the application of silica anode materials for lithium-ion batteries is severely limited. Here, SiO2 nanotubes with a uniform and complete carbon layer were prepared employing ZnO nanorods as templates. The controllable wall thickness of SiO2 nanotubes is about 11 nm, and the thinner wall reduces the lithium-ion diffusion distance and boosts performance. The uniform and complete carbon layer leads to a perfect dispersity of SiO2 nanotubes, enhances the overall electrical conductivity, and also buffers the mechanical stresses caused by volume change, which helps to exhibit high specific capacity and a long cycle life. The nanotubular SiO2@C composite reveals a high discharge specific capacity of about 526.3 mAh g−1 at a current density of 1 A g−1 after 500 cycles without significant capacity fade. In addition, it demonstrates excellent rate performance, which can maintain above 420 mAh g−1 even at a current density of 5 A g−1. The strategy may be adopted to prepare other anode materials as well.