Room‐Temperature Sodium–Sulfur Batteries: Rules for Catalyst Selection and Electrode Design

Abstract

Seeking an optimal catalyst to accelerate conversion reaction kinetics of room‐temperature sodium–sulfur (RT Na–S) batteries is crucial for improving their electrochemical performance and promoting the practical applications. Herein, theoretical calculations of interfacial interactions of catalysts and polysulfides in terms of the surface adsorption state, interfacial ions migration, and electronic concentration around the Fermi level are systematically proposed as guiding principles of catalyst selection for RT Na–S batteries. As a case, MoN catalyst is accurately selected from transition metal nitrides with different d orbital electrons, and for experiment, it is introduced into the carbon nanofibers as a dual‐functioning host (MoN@CNFs). The MoN@CNFs can effectively anchor polysulfides and accelerate their conversion reaction. In addition, for the sodium anode, the MoN@CNFs can also induce uniform deposition of Na and inhibit dendrite growth, which are supported by in situ characterizations and finite element simulation technique. As a result, the as‐prepared RT Na–S battery displays high reversible capacity of 990 mAh g–1 at 0.2 A g–1 after 100 cycles and long lifespan over 1500 cycles at 2 A g–1. Even with high S loading of 5 mg cm–2, the RT Na–S battery still exhibits a high areal capacity of 2.5 mAh cm–2.

Boosting Adsorption and Catalysis of Polysulfides by Multifunctional Separator for Lithium–Sulfur Batteries

“…The stretching vibration bands of S are visible at 150, 219, and 474 cm −1 before the operation. 45,46 These S peaks disappear when the cell discharges to 2.05 V, and they reappear during the subsequent charging to 2.3 V, indicating a highly reversible conversion process. No obvious peaks of LiPS are observed during the cycling process, demonstrating the fast transformation process of polysulfides with the help of the ZIF-67/SA-PAN separator (Figure 4g).…”

Intermetallics Based on Sodium Chalcogenides Promote Stable Electrodeposition–Electrodissolution of Sodium Metal Anodes

“…For Cu 2 S + 2Na + + 2e − → Na 2 S + 2Cu, there are two sloping plateaus corresponding to stepwise sodiation through intermediate solid‐state products such as Na 2 S 2 . [ 83–88 ] During the first desodiation to 1 V, as well as in the four subsequent cycles, both Na 2 Te@CF and Na 2 S@CF deliver negligible capacity, confirming kinetic irreversibility.…”

Carbonized Polymer Dots Enhancing Interface Stability of LiNi0.8Co0.1Mn0.1O2 Cathodes

“…The NCM811@1 wt% CPDs sample showed the lowest R ct value, which suggests that NCM811@1 wt% CPDs can greatly enhance the charge transport coefficient. [ 27 ] As shown in Table S2 (Supporting Information), the $${D}_{{\rm{Li}}^{+}}$$ value of NCM811@1 wt% CPDs before cycling was higher than that of the bare NCM811. The Li + diffusion coefficient of NCM811@1 wt% CPDs is 1.47 × 10 −18 cm s −1 , while that of NCM811 is 1.2 × 10 −18 cm s −1 .…”