Facile synthesis of sandwiched Zn2GeO4–graphene oxide nanocomposite as a stable and high-capacity anode for lithium-ion batteries†
Traditional metal anode materials in lithium-ion batteries are plagued by instability upon discharge–charge cycling. We report that a unique sandwiched Zn2GeO4–graphene oxide nanocomposite has been synthesized on a large scale through a simple ion-exchange reaction, whereby Zn2GeO4 nanorods with lengths of 600 nm and widths of 40 nm are homogeneously sandwiched into the graphene oxide matrix. Compared with bare Zn2GeO4 nanorods, a dramatic improvement in the electrochemical performance of the resulting nanocomposite has been achieved. In the voltage window of 0.001–3 V, the electrode of the Zn2GeO4–graphene oxide nanocomposite delivers a specific capacity as high as 1150 mA h g−1 at 200 mA g−1 after 100 discharge–charge cycles. Even at a high current density of 3.2 A g−1, a capacity of 522 mA h g−1 can be retained. The unusual electrochemical performance including highly reversible capacity and excellent rate capability arise from synergetic chemical coupling effects between Zn2GeO4 and graphene oxide.