A Universal Strategy To Prepare Sulfur-Containing Polymer Composites with Desired Morphologies for Lithium–Sulfur Batteries

Abstract

Lithium-sulfur (Li-S) batteries are probably the most promising candidates for the next-generation batteries owing to their high energy density. However, Li-S batteries face severe technical problems where the dissolution of intermediate polysulfides is the biggest problem because it leads to the degradation of the cathode and the lithium anode, and finally the fast capacity decay. Compared with the composites of elemental sulfur and other matrices, sulfur-containing polymers (SCPs) have strong chemical bonds to sulfur and therefore show low dissolution of polysulfides. Unfortunately, most SCPs have very low electron conductivity and their morphologies can hardly be controlled, which undoubtedly depress the battery performances of SCPs. To overcome these two weaknesses of SCPs, a new strategy was developed for preparing SCP composites with enhanced conductivity and desired morphologies. With this strategy, macroporous SCP composites were successfully prepared from hierarchical porous carbon. The composites displayed discharge/charge capacities up to 1218/1139, 949/922, and 796/785 mA h g at the current rates of 5, 10, and 15 C, respectively. Considering the universality of this strategy and the numerous morphologies of carbon materials, this strategy opens many opportunities for making carbon/SCP composites with novel morphologies.

Metal–Organic Aerogel Assisted Reduced Graphene Oxide Coated Sulfur as a Cathode Material for Lithium Sulfur Batteries

“…The distinct peaks at 1384, 1104, and 653 cm −1 in the image are ascribed to the vibrations of CH, CO, and CS, respectively. 17,44,45 In the structure of Al-MOG, carboxyl, carbonyl, hydroxyl, and other groups interact with the soluble Li 2 S x , which efficaciously intercepts the dissolution of intermediates. Thus, the electrochemical stability of the composite is ameliorated.…”

Three‐Dimensionally Scaffolded Hydrogel@Sulfur Composite as a Binder‐Free Polysulfides‐Adsorptive Cathode for High‐Performance Lithium‐Sulfur Batteries

“…In addition, in Figure S5, Supporting Information, the X‐ray photoelectron spectroscopy (XPS) spectrum of S 2p exhibits peaks at 163.9 and 165.0 eV, which are assigned to elemental S . The two peaks located at high energies of 168.7 and 169.8 eV were attributed to the S species derived from ammonium persulfate . The signals of the S species were observed in both PAN and PAN@S. Through quantification using the XPS results, the S content in the PAN@S composite derived from ammonium sulfate was ≈34.8%.…”

“…The interrelation between current density ( i ) and scanning rate ( v ) can be calculated using the equation: i = av b , where b is determined from the slope of log( i ) vs log( v ) from Figure b. The calculated b for cathodic peaks 1 and 3 and anodic peak 2 are 0.64, 0.45, and 0.57, respectively, indicating that current is predominantly controlled by a diffusion‐controlled process . The total capacitive contribution at a fixed rate was quantified on the basis of the relationship: i ( v ) = k 1 v + k 2 v 1/2 , where k 1 v and k 2 v 1/2 correspond to the current contributions from the surface capacitive effects and the diffusion‐controlled intercalation process, respectively.…”

Synergetic Covalent and Spatial Confinement of Sulfur Species by Phthalazinone-Containing Covalent Triazine Frameworks for Ultrahigh Performance of Li–S Batteries

“…To restrict the shuttle effect more effectively, polymers are selected and designed to afford a high-performance Li–S battery, such as modified layers of cathodes and separators, , polymer electrolytes, , and functional binders. − The sulfur-rich polymers with chemically bonded sulfur species also have been explored. These polymers are mainly produced via vulcanization − or inverse vulcanization − and copolymerization of sulfur with other organic compounds. − Because of the strong covalent chemical interaction, the shuttle effect of polysulfides is efficaciously inhibited. Nevertheless, it is rather difficult to achieve full use of active materials and good electrochemical performance because of their poor conductivity and nonporous structure.…”