Oxygen-rich graphene vertically grown on 3D N-Doped carbon foam for high-performance sodium ion batteries

Graphene is emerged as one of the promising anodes for sodium ion batteries (SIBs) in terms of high electronic conductivity and specific surface area, however, the low initial Coulombic efficiency and inferior cycle capability severely limit its application. Herein, oxygen-rich graphene vertically grown on 3D N-doped carbon foam (VGOG/3DNCF) is prepared via a super simple and scalable method, which just involves hydrogen-bond adsorption of graphene oxide with melamine sponge and subsequent two-step calcination. When VGOG/3DNCF is evaluated as anode for SIBs, the ultra-high oxygen content (16.4 at%) dominated by CO groups renders VGOG/3DNCF much more active sites for Na+ storage, and the vertical growth structure of graphene on 3D carbon foam can effectively reduce the restacking of graphene and promote the rapid migration of Na+. As a result, VGOG/3DNCF anode delivers extraordinary Na+ storage ability with outstanding reversible capability (508.6 mAh g−1 at 0.1 A g−1), superior rate performance (113.3 mAh g−1 at 5.0 A g−1) as well as remarkable cycle stability (329.3 mAh g−1 over 1000 cycles at 1.0 A g−1). The facile method together with the impressive electrochemical performances provide a new way to facilitate the application of graphene in SIBs.