Yolk–shell N-doped carbon coated FeS₂nanocages as a high-performance anode for sodium-ion batteries

Abstract

Rationally designed yolk–shell structured N-doped carbon coated FeS2nanocages demonstrate superior high-rate and long-term cycling performance as anode materials for sodium-ion batteries.

Yolk–shell nanoarchitecture for stabilizing a Ce2S3 anode

“…Figure 3A shows the Raman spectra of Ce 2 S 3 @HMCS, CeO 2 @void@C, and Ce 2 S 3 @C. Two broad peaks at 1350 and 1590 cm −1 , corresponding to the D band (disorder induction) and the G band (graphite), are detected for all three samples 35 . Ce 2 S 3 @C and Ce 2 S 3 @HMCS have similar intensity ratios of the D/G band, which show high graphitization and electronic conductivity 28,36 . Compared with CeO 2 @void@C, the D/G band ratios of Ce 2 S 3 @C and Ce 2 S 3 @HMCS decreased slightly, which may be caused by the continuous sulfuration under high temperatures.…”

“…The signal at 165.2 eV reflects the formation of the C–S bond, which indicates that S atoms are likely introduced into the carbon shell during the sulfuration process. The peak at 168.7 eV is related to SO x caused by the oxidation of sulfur in the air 36 …”

Highly active Fe7S8 encapsulated in N-doped hollow carbon nanofibers for high-rate sodium-ion batteries

“…5(c). It becomes immediately apparent that the ultrahigh-rate capability of our NHCFs/Fe 7 S 8 anode is significantly superior to those of the newly reported SIBs based on iron sulfidebased anodes with the various crystal forms or structures in the literature, including Fe 3 S 4 [38], FeS 2 @FeSe 2 [47], FeS [48], Fe 1Àx S-600 [49], Fe 1Àx S@C [50], Fe 7 S 8 @C-G [51], FeS 2 @NC [52], FeS 2 @C [23], Fe 1Àx S@PCNWs/rGO [21], and Fe 1Àx S@NC@G [53]. The remarkable rate performance in NHCFs/Fe 7 S 8 anode material is due to the Fe 7 S 8 of higher electron conductivity, Na + diffusion kinetics and utilization of ether-based electrolyte.…”

Enhanced sodium storage performance of silk fibroin‐derived hollow iron sulfide with potential window control

“…Recently, novel electrode materials have been investigated for high energy and high power density SIBs. Metal sulfides (eg, MoS 2 , WS 2 , SnS, CoS, TiS 2 , and FeS 2 ) have been extensively investigated for SIB applications as compared to metal oxides because the sodiation product of the former shows better conductivity than that of the latter 5‐12 . Moreover, as the metal‐sulfur bond is weaker than the metal‐oxygen bond, metal sulfides are more promising than metal oxides for the conversion reaction, which requires the bond breaking process 13‐15 …”

“…Metal sulfides (eg, MoS 2 , WS 2 , SnS, CoS, TiS 2 , and FeS 2 ) have been extensively investigated for SIB applications as compared to metal oxides because the sodiation product of the former shows better conductivity than that of the latter. [5][6][7][8][9][10][11][12] Moreover, as the metal-sulfur bond is weaker than the metaloxygen bond, metal sulfides are more promising than metal oxides for the conversion reaction, which requires the bond breaking process. [13][14][15] Among the many metal sulfides investigated for SIB applications, iron sulfides have been extensively studied for SIB applications due to their eco-friendliness, high theoretical capacity, and low cost.…”