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 V (PO ) (NVP), MoS , and TiO ) are anchored onto the 3DPGFs-NS matrix (denoted as NVP@C@3DPGFs-NS; MoS @C@3DPGFs-NS and TiO @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 @C@3DPGFs-NS and TiO @C@3DPGFs-NS deliver capacities of 317 mAhg at 5 Ag after 1000 cycles and 185 mAhg at 1 Ag 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.

Interlayer Expanded SnS2 Anchored on Nitrogen‐Doped Graphene Nanosheets with Enhanced Potassium Storage

“…The formation of C=N bond indicates that the chemical bond has formed by heteroatoms doping into graphene. Moreover, as depicted in Figure f, the N 1s spectrum is also carried out and the spectrum can divide into several peaks at 402.1, 400.3 and 398.8 eV, which can be matched well with graphitic‐N, pyrrolic‐N and pyridinic‐N, respectively ,. The XPS results imply that the intense coupling effect at the heterointerface produced by electron cloud migration via heteroatoms doping will effectively increase the reactive sites for K + storage and extremely accelerate charge transfer.…”

“…Moreover, as depicted in Figure 2f, the N 1s spectrum is also carried out and the spectrum can divide into several 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 peaks at 402.1, 400.3 and 398.8 eV, which can be matched well with graphitic-N, pyrrolic-N and pyridinic-N, respectively. [40,41] The XPS results imply that the intense coupling effect at the heterointerface produced by electron cloud migration via heteroatoms doping will effectively increase the reactive sites for K + storage and extremely accelerate charge transfer. More importantly, based on the intense coupling effect, a sturdy nanostructure of SnS 2 @NC has formed which can vastly keep the structure stability, thus greatly improving the long cyclic electrochemical performances.…”

Multicore–Shell Bi@N‐doped Carbon Nanospheres for High Power Density and Long Cycle Life Sodium‐ and Potassium‐Ion Anodes

“…Figure e,f shows the Nyquist plots of Bi@N‐C electrode for DME and EC/DEC electrolytes, respectively. The depressed semicircle section at high frequency relating to the charge‐transfer resistance ( R ct ) and the inclined line at the low frequency corresponding to the diffusion of sodium ions into bulk electrode are displayed in Nyquist plot . The fresh cell used DME electrolyte presents lower R ct (33 Ω) than that of cell used EC/DEC electrolyte (844Ω) based on the equivalent circuit in Figure S18 in the Supporting Information.…”

Nickel Chelate Derived NiS2 Decorated with Bifunctional Carbon: An Efficient Strategy to Promote Sodium Storage Performance

“…In recent years, different sodium storage mechanisms were proposed and corresponding materials have been developed for SIBs. For instance, intercalation‐type TiO 2 , graphite, conversion‐type Fe 2 O 3 , alloy‐type Sb, P, etc. Particularly, carbon materials, account of its excellent performances and abundant resources, have been widely investigated.…”