Architecting Freestanding Sulfur Cathodes for Superior Room‐Temperature Na–S Batteries

Abstract

Room‐temperature sodium–sulfur (RT Na–S) batteries have attracted extensive attention because of their low cost and high specific energy. RT Na–S batteries, however, usually suffer from sluggish reaction kinetics, low reversible capacity, and short lifespans. Herein, it is shown that chain‐mail catalysts, consisting of porous nitrogen doped carbon nanofibers (PCNFs) encapsulating Co nanoparticles (Co@PCNFs), can activate sulfur via electron engineering. The chain‐mail catalysts Co@PCNFs with a micrograde hierarchical structure as a freestanding sulfur cathode (Co@PCNFs/S) can provide space for high mass loading of sulfur and polysulfides. The electrons can rapidly transfer from chain‐mail catalysts to sulfur and polysulfides during discharge–charge processes, therefore boosting its conversion kinetics. As a result, this freestanding Co@PCNFs/S cathode achieves a high sulfur loading of 2.1 ± 0.2 mg cm−2, delivering a high reversible capacity of 398 mA h g−1 at 0.5 C (1 C = 1675 mA g−1) over 600 cycles and superior rate capability of an average capacity of 240 mA h g−1 at 5 C. Experimental results, combined with density functional theory calculations, demonstrate that the Co@PCNFs/S can efficiently improve the conversion kinetics between the polysulfides and Na2S via transferring electrons from Co to them, thereby realizing efficient sulfur redox reactions.

The promises and challenges of aqueous Zinc-Sulfur batteries

“…[1,2] In recent decades, organic-electrolytebased M-S batteries (such as Li-S batteries and Na-S batteries) have been widely investigated due to their satisfactory performance and mature industrial supply. [3][4][5] Nevertheless, these organic electrolytes are usually toxic and flammable, which may limit their applications. [6,7] Therefore, it is best to explore the aqueous electrolyte-based M-S batteries, which will possess the merits of the high capacity of sulfur and the safety and nonflammability of the aqueous electrolytes.…”

Research Progress of Spin-Dependent Effects in Catalysis and Energy Storage

“…Including the adsorption energy of carbon materials for polysulfides, the energy barrier of the reaction of polysulfides is reduced, and the charge transfer rate is accelerated. [85] In recent work, these experiments [86] encapsulate Co into N-doped carbon nanofibers(Co@PCNFs ) to form chain-mail catalysts that efficiently transfer charge. By non-in situ absorption measurements, as shown in Figure . 7a, the Co@PCNFs exhibit strong absorption after 10 h. The UV-visible spectrum indicates that the residual sodium polysulfide concentration in the solution is low, indicating that the Co@PCNFs/S composite has a strong absorption capacity for NaSx.…”

“…(d) Gibbs free energy diagrams for the transformation between polysulfide intermediates on N-G andCo@N-G hybrids. Reproduced with permission [86]. Copyright 2022, John Wiley and Sons.…”

A Review on the Construction of Carbon-Based Metal Compound Composite Cathode Materials for Room Temperature Sodium-Sulfur Batteries

“…For example, lithium-sulfur (Li-S) batteries, sodium-sulfur (Na-S) batteries and other metal-sulfur-based batteries, their ultra-high theoretical capacity and energy density are profound significance for the development and research of large-scale energy storage systems ( Li, et al, 2019 ; Liu, et al, 2022a ). As far as advanced lithium-sulfur batteries are concerned, they have a high theoretical energy density of 2,600 Wh kg −1 ( Yang, et al, 2021a ), which is expected to replace the bottleneck of lithium-ion batteries in terms of energy density. However, due to the limitation of lithium metal resources and the unfriendly price, the large-scale and large-scale promotion of lithium-sulfur batteries is limited.…”