Low-temperature synthesis of pyrolytic-PVDF-coated SnO2@hard carbon nanocomposite anodes for Li-ion batteries

Herein, SnO2@hard carbon nanocomposites were successfully prepared via a facile and cost-effective method that involved a one-pot hydrothermal treatment of a mixture of Sn4+, cellulose, and polyvinylidene fluoride (PVDF). Detailed material characterizations were carried out using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and N-2 adsorption/desorption isotherms. The results reveal the presence of 4-5 nm SnO2 quantum dots that are uniformly anchored on nanosized hard carbon particles. Moreover, pyrolytic PVDF rendered a highly conductive carbon coating which reduced the hydroxyl and carboxyl groups and resulted in abundant micro- and meso-pores on the hard carbon surface. Then, the as-prepared carbon-coated SnO2@hard carbon nanocomposites are utilized as anode materials in Li-ion batteries, rendering a superior discharge capacity of>600 mAh/g at a current density of 0.1A/g, a high initial coulombic efficiency of similar to 72%, and an excellent capacity retention of>85% after 100 charge/discharge cycles. These results confirm that the as-prepared carbon-coated SnO2@hard carbon nanocomposite is a promising candidate to be used as an electrode for next-generation Li-ion batteries.