In situ wrapping of the cathode material in lithium-sulfur batteries

Abstract

While lithium–sulfur batteries are poised to be the next-generation high-density energy storage devices, the intrinsic polysulfide shuttle has limited their practical applications. Many recent investigations have focused on the development of methods to wrap the sulfur material with a diffusion barrier layer. However, there is a trade-off between a perfect preassembled wrapping layer and electrolyte infiltration into the wrapped sulfur cathode. Here, we demonstrate an in situ wrapping approach to construct a compact layer on carbon/sulfur composite particles with an imperfect wrapping layer. This special configuration suppresses the shuttle effect while allowing polysulfide diffusion within the interior of the wrapped composite particles. As a result, the wrapped cathode for lithium–sulfur batteries greatly improves the Coulombic efficiency and cycle life. Importantly, the capacity decay of the cell at 1000 cycles is as small as 0.03% per cycle at 1672 mA g–1.

Improve redox activity and cycling stability of the lithium‐sulfur batteries via in situ formation of a sponge‐like separator modification layer

“…It is worth mentioning that the signal belonging to the TPP molecule was also observed and ascribed to the unreacted TPP, which was used in excess. As for the KB‐TPS layer, only the fingerprint of TPS was identified in the spectrum, which is a clear evidence of total conversion of TPP into TPS during the synthesis . In line with previous research results, the possible reaction between TPP and Li 2 S 6 was proposed and displayed in Figure S4.…”

“…31 P NMR spectra of the TPP, reaction product between KB‐TPP and Li 2 S 6 (Figure 1J), and KB‐TPS modification layer (Figure 1C and D) were recorded, and they are depicted in Figure 1K. Two specific signals at −5.47 and 42.62 ppm associated with the TPP and TPS, respectively, were detected in the spectrum of the reaction product between KB‐TPP and Li 2 S 6 after 6 hours, indicating the formation of TPS . It is worth mentioning that the signal belonging to the TPP molecule was also observed and ascribed to the unreacted TPP, which was used in excess.…”

“…This result provides a piece of evidence that the sponge‐like functional layer has a relatively high Li + conductivity. This is attributed to the electron‐rich phenyl structure of TPS, which was supposed to facilitate the diffusion of Li + . The D Li+ in the electrolyte environment is another essential parameter for understanding the Li + conduction properties of the separator.…”

Recent Advances in Cathode Materials for Room‐Temperature Sodium−Sulfur Batteries

“…reported the sulfurized polyacrylonitrile (SPAN) composite as cathode material for Li−S batteries. Since then, various SPAN cathodes have been developed for Li−S and RT−Na/S batteries . In 2007, Wang et al .…”

Nitrogen‐doped nanoarray‐modified 3D hierarchical graphene as a cofunction host for high‐performance flexible Li‐S battery

“…3D porous scaffolds are the current research hotspot in Li anode for improving the Li plating/stripping behavior by accommodating volume change and reducing current density. For S cathode, carbon‐based materials with excellent conductivity, such as CNT and graphene, are the most popular hosts to promote conversion reactions and enhance S utilization . To inhibit shuttle effect, it is highly necessary to increase the adsorption by polar substrates such as heteroatom N/P, Co/V/Ni metal compound, and so on .…”