Synthesis of SnO2 pillared carbon using long chain alkylamine grafted graphene oxide: an efficient anode material for lithium ion batteries

Abstract

With the objective of developing new advanced composite materials that can be used as anodes for lithium ion batteries (LIBs), herein we describe the synthesis of SnO₂ pillared carbon using various alkylamine (hexylamine; dodecylamine and octadecylamine) grafted graphene oxides and butyl trichlorotin precursors followed by its calcination at 500 °C for 2 h. While the grafted alkylamine induces crystalline growth of SnO₂ pillars, thermal annealing of alkylamine grafted graphene oxide results in the formation of amorphous carbon coated graphene. Field emission scanning electron microscopy (FE-SEM) results reveal the successful formation of SnO₂ pillared carbon on the graphene surface. X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy characterization corroborates the formation of rutile SnO₂ crystals on the graphene surface. A significant rise in the BET surface area is observed for SnO₂ pillared carbon, when compared to pristine GO. Electrochemical characterization studies of SnO₂ pillared carbon based anode materials showed an enhanced lithium storage capacity and fine cyclic performance in comparison with pristine GO. The initial specific capacities of SnO₂ pillared carbon are observed to be 1379 mA h g⁻¹, 1255 mA h g⁻¹ and 1360 mA h g⁻¹ that decrease to 750 mA h g⁻¹, 643 mA h g⁻¹ and 560 mA h g⁻¹ depending upon the chain length of grafted alkylamine on the graphene surface respectively. Electrochemical impedance spectral analysis reveals that the exchange current density of SnO₂ pillared carbon based electrodes is higher, corroborating its enhanced electrochemical activity in comparison with GO based electrodes.