Elastic Reduced Graphene Oxide Nanosheets Embedded in Germanium Nanofiber Matrix as Anode Material for High-Performance Li-Ion Battery

Abstract

Germanium, as a semiconductor material, has a poor electrical conductivity, but the high theoretical capacity of 1600mAhg−1 makes it as a promising high-capacity anode material for lithium-ion batteries (LIBs). The huge volume variation during charge and discharge leads to a poor cycling stability. In this paper, Ge with reduced graphene oxide nanofibers (Ge@RGO NFs) are firstly prepared by electrospinning. The nanofibers with a uniform diameter of 50nm combined RGO delivered a high specific capacity of 1727.0mAhg−1 in the fist discharging and 1205.1mAhg−1 after 100 cycles at the constant current density of 200mAg−1. RGO in the composites has two important roles: (i) as a conductive agent to improve electrical conductivity; (ii) as a buffer to protect Ge nanostructure from pulverization during charge and discharge processes. Electrochemical testing results show that the Ge@RGO nanofibers anode has a high specific capacity of 661.6mAhg−1 at the current density of 5000mAg−1, suggesting the Ge@RGO electrodes can be used to high current and high-power electronic equipments.