One of the drawbacks of Si-based battery anodes is poor cycle stability due to volume expansion of the anode material. To overcome this limitation, we propose a novel strategy of Si nanotube sheet synthesis using the thermal burst method. Herein, SiO 2 nanotubes are prepared using the hard template method; subsequently, Si nanotube sheets are produced during the thermal burst caused by magnesiothermic reduction, which occurs because nanotubes are broken by ZnO with a larger thermal expansion coefficient. The electrochemical test results indicate that the Si nanotube sheets possess excellent electrochemical properties. The discharge specific capacity can reach 712.7 mAh g −1 even at the current density of 5 A g −1 . Moreover, after carbon coating, a discharge capacity of 695.9 mAh g −1 is retained after 400 cycles at 1 A g −1 and the capacity retention of full batteries can reach 81.78% after 50 cycles at a rate of 0.5 C. Thus, the Si-based anode electrode with excellent electrochemical performance can be prepared by the thermal burst process, and this strategy can be applied to the preparation of other anode materials.
In this paper, the structure of three TiO2 polymorphs are introduced, then the preparation and electrochemical properties of TiO2 with different morphologies and the related research on the composite with carbon and other materials are discussed.
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.
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