Sulfur Microspheres Encapsulated in Porous Silver‐Based Shell with Superior Performance for Lithium‐Sulfur Batteries

Abstract

The lithium‐sulfur system is considered as one of the next‐generation batteries owing to its low‐cost and high theoretical energy density. However, the poor conductivity of sulfur, undesirable dissolution, and shuttling of lithium polysulfides are still main challenges for a practical application. Herein, a chemical plating method was developed to encapsulate sulfur microspheres within a porous Ag‐based thin shell of ca. 67 nm in thickness (denoted as S@Ag microcomposites). The sulfur content in the S@Ag particles is 89 wt%. With such structural and compositional merits, the core‐shell composites can effectively facilitate the electron transfer and alleviate the polysulfide dissolution. When utilized as cathode in Li−S batteries, the S@Ag microcomposites exhibit good electrochemical performance, featured by an initial charge capacity of 1231 mAh g−1 and a capacity of 922 mAh g−1 after 100 cycles at 0.2 C. The electrochemical performance of commercial S particles was also improved after treated by this chemical plating method. This study provides a simple and novel approach to fabricate S composite cathodes with high S content and promising electrochemical properties.

Lightweight freestanding hollow carbon fiber interlayer for high‐performance lithium‐sulfur batteries

“…To explore the porous structure HCFs in detail, pore size distributions and BET sorption isotherms of HCFs are shown in Figure 2. The typical type I and type IV nitrogen sorption isotherms and H3 type hysteresis loop were obtained (Figure 2A), which indicates the micro‐ and mesoporous structure of HCFs 29‐31 . A detailed description of HCFs in specific surface area, and pore size are shown in Table 1.…”

“…The typical type I and type IV nitrogen sorption isotherms and H3 type hysteresis loop were obtained (Figure 2A), which indicates the microand mesoporous structure of HCFs. [29][30][31] A detailed description of HCFs in specific surface area, and pore size are shown in Table 1. The pore volumes and specific surface areas of HCF-600 and HCF-700 are inferior to other HCFs at higher temperatures.…”

Facile Synthesis of Hierarchical Sulfur Composites for Lithium–Sulfur Batteries

“…A typical CV with two main reduction peaks during the cathodic scan was obtained for all cells. The peak at the higher cathodic voltage was attributed to the reduction of elemental S to a higher-order PS (Li 2 S x , 4 � x < 8), and the one at lower voltage is associated with the further reduction of the high-order PSs to the lower-order compounds Li 2 S 2 and Li 2 S. [19,20] The reduction peaks of the S/CB, S@C rhom , S@C aggl , and S@C disp cells were located at 2.25 and 1.89 V, 2.28 and 2.03 V, 2.26 and 2.02 V, and 2.31 and 2.05 V, respectively. In the anodic scan, except for the S@C rhom cell, the cells exhibited a single oxidation peak associated with the multiple reactions of Li 2 S 2 or Li 2 S to form Li 2 S x .…”

“…To achieve energy requirements, the development of new electrode materials with higher capacity is a prerequisite. However, S also presents a number of challenges that have to be overcome, such as its low electrical conductivity (5 × 10-30 S cm À 1 ), [15] the shuttle effect caused by easy dissolution of the intermediates (high-order polysulfide (PS) species) generated during discharge, [16][17][18][19][20] and the high volume expansion (80 %). [8] Among the many active cathode materials, elemental sulfur (S) is a highly promising candidate due to its extremely high theoretical capacity of 1672 mAh g À 1 , which is more than ten times greater than that of most commercial cathode materials.…”

“…[9][10][11][12][13][14] In addition to its high specific capacity, S presents other attractive advantages, including its low cost, nontoxicity, and great abundance in the earth's crust. However, S also presents a number of challenges that have to be overcome, such as its low electrical conductivity (5 × 10-30 S cm À 1 ), [15] the shuttle effect caused by easy dissolution of the intermediates (high-order polysulfide (PS) species) generated during discharge, [16][17][18][19][20] and the high volume expansion (80 %). [21] The shuttle effect, relating to the dissolution of high-order PS species that are produced as electrochemical intermediates in a polar electrolyte and the followed migration to the lithium anode due to the concentration gradient, results in a continual loss of the active S material from the cathode and thus the eventual decay of the capacity.…”