Nitrogen-doped holey graphene foams for high-performance lithium storage†
Although lithium ion batteries have gained commercial success in abundant portable devices, they still lack suitable electrode materials with high capacities and rate capabilities critical for broad applications. Herein, we demonstrate a facile and scalable approach toward nitrogen-doped holey graphene foams (NHGFs) via simultaneous etching and assembling of graphene oxide and subsequent annealing treatments. The resultant NHGFs possess some unique structural features such as hierarchically interconnected pores in the foams and a nitrogen-doped holey structure in the basal plane of the graphene walls, which facilitate the fast diffusion of both lithium and electrons through the NHGFs and meanwhile significantly improve electrochemical activity. As a result, the NHGFs exhibit excellent electrochemical performances for lithium storage, including a high reversible capacity (1194 mA h g−1), good high-rate capability (420 mA h g−1 at 5C) and long cycling stability with negligible capacity loss after 1000 continuous cycles.