Interconnected structure Si@TiO2-B/CNTs composite anode applied for high-energy lithium-ion batteries

Abstract

As an anode with ultrahigh capacity (4200 mAh g−1), silicon (Si) has inherent defects, such as drastic volume change (~300%) and poor conductivity. To cope with these problems, constructing a rigid shell (e.g. TiO2) on the surface of Si particles is an effective method. Typically, monoclinic titanium dioxide (TiO2-B) has the more excellent electrochemical performance among the various crystalline of TiO2 (anatase, rutile, etc.) for its open channel and characteristic pseudocapacitive effect. In addition, carbon nanotubes (CNTs) are good conductor of electricity. It is hopeful to increase the conductivity of the Si anode by adding CNTs. In this work, therefore, a Si@TiO2-B/CNTs composite is prepared by hydrothermal method. The composite exhibits superior electrochemical properties during the half-cell test (1184 mAh g−1 under 0.1 A g−1 at 200th cycles). Furthermore, the electrochemical kinetics of the materials were studied by cyclic voltammetry, which demonstrated that coating TiO2-B could increase the capacitive effects of the composite (68.75%).