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A SiO/graphite/amorphous carbon (SiO-C) hybrid anode with superior electrochemical performance is successfully realized by using a low-cost and simple method. Here, we apply a pretreatment of commercialized graphite by ball-milling to realize evenly dispersion of the components and good effect of carbon coating, thus resulting in excellent cycling stability. Specifically, the as-prepared sample shows a high reversible capacity of 850 mA h g −1 after 100 cycles at 100 mA g −1 and excellent rate capability of 730 mA h g −1 even at 500 mA h g −1 . Additionally, a relatively high initial coulombic efficiency of 77% is delivered among SiO-based anode materials. High-resolution transmission electron microscope (HRTEM) technique is used to further visually verify the conversion behavior of SiO in the first cycle: scattered amorphous silicon particles with size about 5 nm and irreversible Li 4 SiO 4 as the detected resultants. The result of electrochemical impedance spectroscopy (EIS) reveals that the polarization resistance (Rp) decreases with pre-treated graphite. This work presents a facile approach to prepare Si-based anode material for new generation lithium-ion batteries with high energy density and more insights into the conversion behavior of SiO. [ABSTRACT FROM AUTHOR]

A Si–Co–C composite material has been prepared by a simple high energy mechanical milling process (HEMM). The crystal structures and morphologies of the samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), indicating that silicon and cobalt elements uniformly distribute in graphite sheets. Electrochemical tests show that the initial discharge and charge capacities of the Si 20 Co 10 C 70 composite are 1283.3 mAh g −1 and 1068.8 mAh g −1 , respectively, with an initial coulombic efficiency of 83.3%. It maintains a reversible capacity of 620 mAh g −1 after 25 cycles and remains stable above 610 mAh g −1 after 50 cycles. The results of cyclic voltammetry (CV) prove that cobalt acts as an inactive matrix, and the result of electrochemical impedance spectroscopy (EIS) reveals that the polarization resistance (Rp) decreases after the Co addition. It is believed that uniform dispersed cobalt nanoparticles relieve the destruction of the graphite. Furthermore, the existence of carbon and cobalt not only restrains the agglomeration of Si particles, but also suppresses the volume expansion of Si. This extraordinary microstructure is believed to be responsible for the excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

Silicon/lithium titanate (Si/Li 2 TiO 3 ) nanocomposite is successfully prepared through the combination of a sol–gel approach with a high-temperature treatment as well as a high energy ball milling process. The structure and morphology of the composite are characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) analysis reveals Si particles are coated by the uniform disordered Li 2 TiO 3 layer with a thickness of about 5 nm. The investigation in cycling performances demonstrates that Si/Li 2 TiO 3 exhibits the improved cycling stability, with specific capacity of 471.0 mA h g −1 after 50 cycles and the capacity retention is 31.5%, much higher than pure Si. Compared with pure Si, Si/Li 2 TiO 3 shows better rate-capability, a reversible capacity of 315.2 mA h g −1 at 0.8 A g −1 is maintained. The higher ionic conductivity of Li 2 TiO 3 is responsible for the improved rate performance. In addition, the results derived from XRD, the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) indicate that lithium ions could react reversibly with Si, and electrochemically less active Li 2 TiO 3 turns into the Li–Ti–O ternary phase, which acts as a buffer matrix in the Si/Li 2 TiO 3 composite, thus improving the reversibility of electrode. [ABSTRACT FROM AUTHOR]