Hierarchically structural Ge encapsulated with nitrogen-doped carbon for high performance lithium storage

The anode of Ge has attracted extensive attention due to its high theoretical capacity and energy density. A composite of hierarchically structural Ge encapsulated with nitrogen-doped carbon has been successfully synthesized by using a scalable method. Such a composite properly combines the two superiorities of hierarchically structural Ge and nitrogen-doped carbon, showing a superior electrochemical performance. Designed as an anode for lithium ion batteries, a high reversible capacity of 1067mAhg−1 after 300cycles at 1Ag−1, an outstanding rate capabilities of 1270mAhg−1 at 0.1Ag−1 and 605mAhg−1 at 20Ag−1 and a stably long-term capacity of 912mAhg−1 after 600cycles at 2Ag−1 were achieved. The hierarchically structural electrode could promote the diffusion of electrolyte into anode of Ge particles, and the nitrogen-doped carbon could strengthen the stability of structure and enhance electrical conductivity of the composite. This work could pave a new route for developing Ge-based anodes in next-generation lithium ion batteries and high-energy-storage devices. [Display omitted] •The composite was composed of hierarchically structural Ge encapsulated by N-doped carbon.•The synergistic effects between hierarchically structural Ge and N-doped carbon shell•The composite anode exhibited a high reversible capacity of 1064mAhg−1 at 1Ag−1.•A capacity of 605mAhg−1 can be remained even at a rate as high as 20Ag−1.