Freeze-drying-assisted synthesis of hierarchically porous carbon/germanium hybrid for high-efficiency lithium-ion batteries

Herein, an approach is reported to prepare porous a carbon/Ge (C/Ge) hybrid. In this hybrid, Ge nanoparticles are closely embedded in a highly conductive and flexible carbon matrix. Such a hybrid features a high surface area (128.0 m² g^-1) and a hierarchical micropore-mesopore structure. When used as an anode material in lithium-ion batteries (LIBs), the as-prepared hybrid [C/Ge (60.37%)] exhibits an improved lithium storage performance with regard to its capacity and rate capability compared to its counterparts. More specifically, it can maintain a specific capacity as high as 906 mAh g^-1 at a high current density of 0.6 A g^-1 after 50 cycles. The excellent lithium storage performance of the C/Ge (60.37%) sample can be attributed to synergetic effects between the carbon matrix and Ge nanoparticles. The method we adopted is simple and effective, and can be extended to fabricate other nanomaterials.