Nitrogen and Sulfur Co-Doped Graphene Nanosheets to Improve Anode Materials for Sodium-Ion Batteries

Abstract

Sodium-ion batteries (SIBs) attract more attention because of sodium’s abundant availability, affordable price, and potential to be an effective anode material. Meanwhile, carbon-based materials provide the most promising anode materials. Because of the large radius of sodium ions, SIBs do not exhibit favorable electrochemical performance. Introducing heteroatoms into the carbon-lattice is an effective strategy to enlarge the interlayer space of carbon-based materials which can improve carbon’s electrochemical performance. In addition, anode materials with a surface-induced capacitive process can enhance the SIB’s electrochemical performance because its capacitive process increases the kinetics of ion diffusion. Here, we describe an SIB’s anode material containing nitrogen and sulfur co-doped graphene sheets [denoted as poly­(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT)/reduced graphene oxide (RGO)] which are synthesized via carbonization of PDMcT polymerized on the surface of GO. PDMcT/RGO exhibited high capacities (240 mA h g–1 at 500 mA g–1), improved rate performance (144 mA h g–1 at 10 A g–1), and good cycling stability (153 mA h g–1 after 5000 cycles at 5000 mA g–1). These unique results are attributed to the enlarged interlayer spacing and electronic conductivity from the heteroatoms which facilitate the sodium ion’s insertion and electron transport. These results represent that PDMcT/RGO is a great potential anode material for SIBs.

Stabilising Cobalt Sulphide Nanocapsules with Nitrogen-Doped Carbon for High-Performance Sodium-Ion Storage

“…The elemental content of nitrogen species on carbon is as high as 13.3% in the Co 9 S 8 @NC-9 sample. Large quantities of extrinsic defects can be introduced into carbon framework by pyridinic/pyrrolic nitrogen doping, hence favours ion transfer, and enhances the interaction property with sodium ions [17,33,34]. Raman spectra of Co 9 S 8 @NC samples are presented in Fig.…”

“…On the other hand, doping of carbon materials with heteroatoms such as nitrogen, sulphur, phosphorous, or boron can improve ionic and electronic conductivity [14][15][16]. Also, doping-induced defects on carbon could create localised active sites to accommodate sodium ions and favour ion transfer, giving rise to higher sodium storage performance [17,18].…”

Double Morphology of Co9S8 Coated by N, S Co-doped Carbon as Efficient Anode Materials for Sodium-Ion Batteries

“…So far, most studies have also focused on designing novel carbon materials with heteroatom (N, P, S, B) doped, such as sandwich-like structures with N, S-doped RG O [33,34], nanoflower-like N-C/CoS 2 [35], Co 9 S 8 coated with N-doped carbon nanospheres [36,37], and N, S-doped nanofibers [38,39]. Carbon coating can not only enhance the conductivity of TMSs, but also remit the stress stemming from the volume expansion.…”

Electrode Materials for High-Performance Sodium-Ion Batteries

“…Furthermore, a strategy to develop a high performance anode for SIBs is to employ doped-graphene. In recently published work [155], co-doped graphene oxide nanosheets with heteroatoms were employed. By adding a polymer containing nitrogen and sulfur, the monomer was adsorbed on the surface of graphene oxide, following a polymerization reaction.…”

“…By adding a polymer containing nitrogen and sulfur, the monomer was adsorbed on the surface of graphene oxide, following a polymerization reaction. The electrochemical results for the SIB anode unveil a capacity retention of 82% after 800 cycles and, for a current density of 500 mAg −1 , a specific capacity of 237.2 mAh g −1 [155]. The results of this work have been provided in Figure 7 as a representative.…”