Design Nitrogen (N) and Sulfur (S) Co‐Doped 3D Graphene Network Architectures for High‐Performance Sodium Storage

Abstract To develop high‐performance sodium‐ion batteries (NIBs), electrodes should possess well‐defined pathways for efficient electronic/ionic transport. In this work, high‐performance NIBs are demonstrated by designing a 3D interconnected porous structure that consists of N, S co‐doped 3D porous graphene frameworks (3DPGFs‐NS). The most typical electrode materials (i.e., Na 3 V 2 (PO 4 ) 3 (NVP), MoS 2 , and TiO 2 ) are anchored onto the 3DPGFs‐NS matrix (denoted as NVP@C@3DPGFs‐NS; MoS 2 @C@3DPGFs‐NS and TiO 2 @C@3DPGFs‐NS) to demonstrate its general process to boost the energy density of NIBs. The N, S co‐doped porous graphene structure with a large surface area offers fast ionic transport within the electrode and facilitates efficient electron transport, and thus endows the 3DPGFs‐NS‐based composite electrodes with excellent sodium storage performance. The resulting NVP@C@3DPGFs‐NS displays excellent electrochemical performance as both cathode and anode for NIBs. The MoS 2 @C@3DPGFs‐NS and TiO 2 @C@3DPGFs‐NS deliver capacities of 317 mAhg −1 at 5 Ag −1 after 1000 cycles and 185 mAhg −1 at 1 Ag −1 after 2000 cycles, respectively. The excellent long cycle life is attributed to the 3D porous structure that could greatly release mechanical stress from repeated Na + extraction/insertion. The novel structure 3D PGFs‐NS provides a general approach to modify electrodes of NIBs and holds great potential applications in other energy storage fields.