In situ reaction synthesis of GeO2/RGO nanocomposite for high performance lithium storage

Germanium dioxide/reduced graphene oxide (GeO2/RGO) nanocomposites are promising anode materials for applications in lithium ion batteries because they have ultrahigh lithium ion storage capacity and high structural stability. However, the design of GeO2 based anodes with satisfactory cycling ability and high capacity still presents a big challenge because of strict requirements in the need for a special type of solvent, a complicated preparation process, high energy and material costs, and/or difficulty in process upscaling. In the present work, GeO2/RGO nanocomposite is successfully synthesized as an anode material by a simple and green method, which stacked the GeO2 nanoparticles directly on the reduced graphene oxide sheets in an in situ process. The sample exhibits high specific capacity and enhanced rate capacity as an electrode material for lithium ion batteries. GeO2/RGO nanocomposite shows a higher storage capacity of 1020.4 mA h g−1 (theoretical capacity 1125 mA h g−1) after 30 cycles with a current density of 0.1 A g−1, and a long-term cycle capacity of 464 mA h g−1 even after 100 cycles at 1 A g−1. This good electrochemical performance is due to the superior properties of non-aggregated graphene sheets and homogeneously dispersed GeO2 nanoparticles in GeO2/RGO nanocomposite.