Copper germanate nanowire/reduced graphene oxide anode materials for high energy lithium-ion batteries

Abstract

Single-crystalline copper germanate (CuGeO₃) nanowires were produced and combined with reduced graphene oxide (RGO) via a one-pot hydrothermal route and were used as anode materials for Li-ion batteries (LIBs). After the initial discharge process of CuGeO₃, both in situ formed CuO and Ge nanocrystals can serve as the hosts for Li ions, resulting in a large Li storage capacity and a stable cyclability of CuGeO₃. The Li storage kinetics of the composite are further enhanced with the RGO conductive network. The CuGeO₃@RGO composite exhibited high lithium storage capacity and remarkable cycling performance, and retained 780 mA h g⁻¹ after 130 cycles under the current density of 100 mA g⁻¹. The improved performance of the CuGeO₃ nanowires is attributed to the synergetic Li storage effect of the in situ formed CuO and Ge, good electronic conduction of Cu nanocrystals along the length of each nanowire, short Li insertion distances, high interfacial contact area with the electrolyte and improved material durability.