Hybrid Membrane with SnS₂ Nanoplates Decorated Nitrogen-Doped Carbon Nanofibers as Binder-Free Electrodes with Ultrahigh Sulfur Loading for Lithium Sulfur Batteries

Abstract

Lithium sulfur batteries have been regarded as promising energy storage devices due to their superiority in energy density. However, the low sulfur loading, low active material utilization, and poor cycling stability restrict their commercial applications. Herein, we prepared a three-dimensional structure of SnS 2 nanoplates decorated on nitrogen-doped carbon nanofibers (3D SnS 2 @N-CNFs) by an electrospinning process followed by a hydrothermal technique. The 3D freestanding SnS 2 @N-CNFs were applied as the current collector and polymeric binder containing a Li 2 S 6 catholyte for lithium polysulfide batteries. The obtained SnS 2 @N-CNFs show the strong physicochemical adsorption of polysulfides and can effectively reduce the electrochemical polarization. The cell with SnS 2 @N-CNFs exhibits high electrochemical performance. As a result, SnS 2 @N-CNFs with high sulfur loading of approximately 7.11 mg displayed the first discharge capacity of 1010 mAh g −1 at 0.2 C with 0.08% capacity decay per cycle over 150 cycles. Meanwhile, the electrode with sulfur loading up to 22.65 mg also exhibits an extremely high capacity of 14.67 mAh, much higher than commonly presented blade-cast sulfur electrodes. The fibrous membrane is promising for assembling with high sulfur loading, which exhibits a superior electrochemical performance in lithium sulfur batteries.

Synergistic effect of titanium‐oxide integrated with graphitic nitride hybrid for enhanced electrochemical performance in lithium‐sulfur batteries

“…The capacities values are represented as Q a and Q b with corresponding the high voltage platform and low voltage platform, respectively, and the values of Q b /Q a are commonly reflected kinetic redox reactions of polysulfide during the redox process. 45,46 TOCN@S has higher Q b /Q a (2.53) than CN@S electrode (2.14), which demonstrated the acceleration of reactions kinetic by TOCN. Cycling performances of the cells were tested at current rate of 0.5 C ( Figure 4C).…”

“…In Figure 4B, the discharging voltage platforms corresponding to the two kinds of electrodes are consistent with the CV curves. The capacities values are represented as Q a and Q b with corresponding the high voltage platform and low voltage platform, respectively, and the values of Q b / Q a are commonly reflected kinetic redox reactions of polysulfide during the redox process 45,46 . TOCN@S has higher Q b / Q a (2.53) than CN@S electrode (2.14), which demonstrated the acceleration of reactions kinetic by TOCN.…”

Nanosized Ti 4 O 7 supported on carbon nanotubes composite modified separator for enhanced electrochemical properties of lithium sulfur battery

“…The first step at high voltage platform is refer to the transformation from cyclo‐octasulfur to long‐chain polysulfides (S n 2− , 4 ≤ n < 8). In the second step at low voltage platform, long‐chain polysulfides are gradually reduced to insoluble Li 2 S 2 or Li 2 S. In the anodic sweep, the peaks between 2.33 and 2.46 V are in connection with the oxidative process from Li 2 S 2 or Li 2 S to elemental sulfur 38 . In comparison to PE separator, the cell using oCNTs‐Ti 4 O 7 separator exhibits the higher reductive peak potential at 2.32 and 2.02 V. The lower voltage hysteresis of oCNTs‐Ti 4 O 7 separator (314 mV) than PE separator (397 mV) indicates that the oCNTs‐Ti 4 O 7 layer can reduce battery polarization and maintain electrochemical stability.…”

“…In the anodic sweep, the peaks between 2.33 and 2.46 V are in connection with the oxidative process from Li 2 S 2 or Li 2 S to elemental sulfur 38. In comparison to PE separator, the cell using oCNTs-Ti 4 O 7 separator exhibits the higher reductive peak potential at 2.32 and 2.02 V. The lower voltage hysteresis of oCNTs-Ti 4 O 7 separator (314 mV) than PE separator (397 mV) indicates that the oCNTs-Ti 4 O 7 layer can reduce battery polarization and maintain electrochemical stability.…”

Recent Advances of Freestanding Cathodes for Li‐S Batteries

“…Yao et al [70] . synthesized nitrogen‐doped carbon nanofibers modified by SnS 2 nanosheets as self‐supporting cathode materials for LSBs by a simple electrostatic spinning and hydrothermal method (Figure 6a).…”