A Facile Immobilization Strategy for Soluble Phosphazene to Actualize Stable and Safe Lithium–Sulfur Batteries

Abstract

Lithium–sulfur batteries (LSBs) have attracted extensive attention owing to their high energy density and abundant sulfur resources. However, LSBs are still restricted by the unsatisfactory electrochemical performance resulting from the shuttle effect of lithium polysulfide (LiPSs), and the potential fire hazard caused by inflammable ether electrolytes and polyolefin separators. Herein, a facile immobilization strategy for hexachlorocyclotriphosphazene (HCCP) is creatively applied to address the above issues simultaneously. Insoluble HCCP cross‐linked microspheres (H‐CMP) are firstly obtained at ambient temperature using tannic acid (TA) as a cross‐linking agent and then a multifunctional separator coating is constructed based on H‐CMP. The released phosphorus‐related radicals from H‐CMP in wide temperatures effectively prevent the combustion of electrolytes and separators, and hence improve the fire safety of the Li–S pouch cell. Furthermore, H‐CMP availably chemisorbs LiPSs to interdict the shuttle effect, thereby dramatically improving the electrochemical performance of LSBs. The effectiveness of this strategy is also verified in high sulfur loading (6.38 mg cm‐2), high temperature (50 °C), and Li–S pouch cells. More importantly, H‐CMP exhibits sufficient stability for Li metal and suppression of Li dendrites. This facile immobilization strategy for multifunctional phosphazenes provides a competitive option for the large‐scale fabrication of high‐safety and high‐performance LSBs.

Oxygen-incorporated crystalline/amorphous heterophase cobalt vanadium selenide nanoplates with dense interfacial sites for robust lithium–sulfur batteries

“…5e. 11,[54][55][56][57][58][59][60][61][62] The cycling performance of the Li-S batteries with different separators at 0.2C is shown in Fig. 5f.…”

“…5h and Table S3 †). 36,[54][55][56][57][58][59][60][61][62] These results indicate that the DC/A O-CoVSe NP modied separator can effectively suppress the shuttle effect and catalyze the conversion of LiPSs.…”

Advancements in flame-retardant strategies for lithium–sulfur batteries: from mechanisms to materials

“…7b). Zhu et al 146 coated cross-linked multiscale free radical microspheres (H-CMP) on a PP separator. H-CMP could improve the wettability of the separator by the electrolyte to accelerate the transmission of Li ions and trap LiPSs (Fig.…”

In Situ Growth Strategy to Construct “Four‐In‐One” Separators with Functionalized Polyphosphazene Coatings for Safe and Stable Lithium–Sulfur Batteries

“…Our previous work has addressed some of the battery safety issues by constructing separator coatings with flame retardants. [18][19][20] Even so, these work do not avoid the poor conductivity of sulfur and lithium sulfide, which results in the unsatisfactory electrochemical performance of LSBs. Hence it is essential to develop multifunctional materials for LSBs with high fire safety and excellent electrochemical properties.…”