Reduced graphene oxide supported tin oxide-boron oxide flexible paper anodes for Li-ion batteries

Abstract

Freestanding tin oxide-boron oxide/reduced graphene oxide (SnO$_{2}$-B$_{2}$O$_{3}$/rGO) nanocomposite anode was produced for Li-ion cells. This binder-free flexible paper anode structure was fabricated by combining SnO$_{2}$-B$_{2}$O$_{3}$ composite and graphene oxide which were synthesized through the sol-gel method and Hummers' method, respectively. Field emission gun scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive X-ray spectrometer, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction were utilized to characterize anode materials. The Williamson-Hall (W-H) analysis was applied using XRD data to determine crystal size and strain of the lattice. Electrochemical tests, cyclic voltammetry, and electrochemical impedance spectroscopy measurements were performed to determine electrochemical properties of the anodes. The results indicated that the anode formed with SnO$_{2}$-B$_{2}$O$_{3\, }$particles anchored on the rGO layers provided higher discharge capacity (838 mAh g$^{-1})$ than that of SnO$_{2}$/rGO (395 mAh g$^{-1})$ after 100 cycles. The electron-deficient nature of boron supplied an effective increase in electrochemical energy storage performance.