SnS₂- Compared to SnO₂-Stabilized S/C Composites toward High-Performance Lithium Sulfur Batteries

Abstract

The common sulfur/carbon (S/C) composite cathodes in lithium sulfur batteries suffer gradual capacity fading over long-term cycling incurred by the poor physical confinement of sulfur in a nonpolar carbon host. In this work, these issues are significantly relieved by introducing polar SnO2 or SnS2 species into the S/C composite. SnO2- or SnS2-stabilized sulfur in porous carbon composites (SnO2/S/C and SnS2/S/C) have been obtained through a baked-in-salt or sealed-in-vessel approach at 245 °C, starting from metallic tin (mp 231.89 °C), excess sulfur, and porous carbon. Both of the in situ-formed SnO2 and SnS2 in the two composites could ensure chemical interaction with lithium polysulfide (LiPS) intermediates proven by theoretical calculation. Compared to SnO2/S/C, the SnS2/S/C sample affords a more appropriate binding effect and shows lower charge transfer resistance, which is important for the efficient redox reaction of the adsorbed LiPS intermediates during cycling. When used as cathodes for Li-S batteries, the SnS2/S/C composite with sulfur loading of 78 wt % exhibits superior electrochemical performance. It delivers reversible capacities of 780 mAh g(-1) after 300 cycles at 0.5 C. When further coupled with a Ge/C anode, the full cell also shows good cycling stability and efficiency.

MCNT/MoS2 promoting the electrochemical performance of lithium-sulfur batteries by adsorption polysulfide

“…This means that both MoS 2 /S and MCNT/MoS 2 /S electrode have good reversibility. The position of the peak is consistent with that recorded in the previous literature [45][46][47]. In CV curves of MCNT/S and MCNT/MoS 2 /S, the cathodic and anodic peaks position are almost the same.…”

“…Nevertheless, the cathodic and anodic peak value of MCNT/MoS 2 /S (peaks I: 1.7 mA; peak III: 3.6 mA) are higher than MCNT/S (peaks I:1.4 mA; peak III:1.9 mA) in figure 4(d). It suggested that the electrochemically active of MCNT/MoS 2 is higher than MCNT [45]. The CV curves of MoS 2 /S cathode and MCNT/MoS 2 /S cathode are almost identical for the first three cycles respectively, exhibiting relatively good capacity retention.…”

Chemical Immobilization Effect on Lithium Polysulfides for Lithium–Sulfur Batteries

“…The spectroscopic studies and first‐principles calculations consistently demonstrate the coupled chemical interaction of Co 9 S 8 with Li 2 S n that relies on S n 2− –Co δ + and Li + –S δ − (of Co 9 S 8 ) binding. Here, the as‐synthesized Co 9 S 8 exhibits far superior LiPS's adsorbent ability than the most popular carbon materials, enabling LSB cathodes to have stable cycling performance …”

Structural Design of Lithium–Sulfur Batteries: From Fundamental Research to Practical Application

“…The design of multi-architectural and multi-functional cathode materials has the potential to overcome these challenges and has been one of the most researched strategies in recent years. Currently, physical routes including capillary force absorption [14,[51][52][53][54][55][56][57], shell coating [58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75], and chemical routes containing heteroatom-doped carbons [76][77][78][79][80][81][82][83][84][85][86][87][88][89][90] and metal-based additives [91][92][93][94][95][96][97][98][99]…”