In Situ One-Step Synthesis of a Ge/Zn2GeO4/N-Doped Carbon Composite as an Anode Material for Lithium-Ion Batteries

Zinc orthogermanate (Zn 2 GeO 4 ) is an attractive anode material for lithium-ion rechargeable batteries. Nevertheless, owing to its disadvantages of low electrical conductivity and large volume change in cycles, it is subjected to poor cycling stability and rate capability, which restrict its rapid development. Herein, an in situ one-step synthetic route is presented for preparing Ge/Zn 2 GeO 4 /N-doped carbon composite by direct carbonization of a mixture of Zn-based metal–organic framework (MET-6) and commercial GeO 2 under N 2 atmosphere. The composite prepared at 800 °C exhibits a uniform spherical morphology comprising Ge/Zn 2 GeO 4 crystals that are tightly covered by thin layers of nitrogen-doped carbon. The Ge/Zn 2 GeO 4 /N-doped carbon anode displays a large charge capacity of 901.9 mAh g –1 over 100 cycles at 0.1 A g –1, long-term stability over 1000 cycles at 1.0 A g –1, as well as good rate capability. Additionally, the assembled full cell with a LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode and Ge/Zn 2 GeO 4 /N-doped carbon composite anode also shows good electrochemical performance.