Hydrothermal Synthesis and Characterization of Co2GeO4/Rgo@C Ternary Composite As Negative Electrodes for Li-Ion Batteries

Abstract

In this present work, pristine Co2GeO4, binary Co2GeO4/reduced graphene oxide (rGO) composite and ternary composite of Co2GeO4/rGO@C is prepared by single step hydrothermal process followed by calcination. The amount of carbon content and rGO is identified through thermogravimetric analysis (TGA). XRD analysis reveals the compound formation of single phase Co2GeO4. TEM and HRTEM images clearly elucidate the presence of ternary phases of Co2GeO4, r-GO and C in the ternary composite. The Galvanostatic charge-discharge (GCD) curve demonstrates that the initial discharge capacity of pristine Co2GeO4, Co2GeO4/rGO and Co2GeO4/rGO@C composite is 1400, 1284 and 1594 mAh g-1 at 50 mAh g-1, respectively. The observed discharge capacity is higher than the theoretical capacity of Co2GeO4 which is due to reduction of organic electrolyte and the formation of solid electrolyte interphase film (SEI). The cycling stability curve shows the specific capacity of 609, 970 and 1180 mAh g-1 for pristine, Co2GeO4/rGO and Co2GeO4/rGO@C composite respectively over 15 cycles which confirms that Co2GeO4/rGO@C composite exhibits the stable and high specific capacity. The rate capability curve and EIS spectrum is carried out for the prepared samples which indicates that Co2GeO4/rGO@C composite shows the better rate capability and good electronic conductivity.