Electrospun Sulfurized Polyacrylonitrile Nanofibers for Long-Term Cycling Stability and High-Rate Lithium–Sulfur Batteries

Abstract

As a promising cathode material for lithium−sulfur (Li-S) batteries, sulfurized polyacrylonitrile (SPAN) with uniform dispersion of short-chain sulfur moieties on its organic skeletons can effectively avoid lithium polysulfides dissolution and exhibit high specific capacity and long-term cycling stability. However, the practical battery performance of the SPAN cathode is dramatically limited by its relatively poor ionic and electronic accessibility. In this work, a three-dimensional (3D) network of Se 0.05 S 0.95 PAN nanofibers incorporated with commercial and low-cost Ketjen black (KB), denoted as ES-KBS@Se 0.05 S 0.95 PAN, is prepared through the electrospinning method. This unique 3D nanofiber structure is beneficial to transport lithium ions and electrons and accommodate volume expansion during lithiation/delithiation processes for Li-S batteries, leading to tremendous improvement of sulfur utilization, rate capability, and long-term cycling performance. ES-KBS@Se 0.05 S 0.95 PAN exhibits an ultrahigh reversible capacity of 1491 mAh g −1 at 0.1C and 1130 mAh g −1 at 5C and retains 1224 mAh g −1 after 500 cycles at 1C, corresponding to a capacity retention of 96.4%. This work proposes a facile strategy for the preparation of sulfur cathodes applicable in lithium−sulfur batteries.

Molecular structure-controlled synthesis of sulfur-containing polymers for rechargeable Li–S batteries

“…The natural stability of carbon chains can effectively improve the structural stability and electrochemical performance of cathode materials. Many types of organic polymers can be used for the preparation of sulfur-containing polymers with carbon chains as the main chains, such as polyacrylic acid (PAA), [80][81][82][83] polyacrylonitrile (PAN), [84][85][86] polypyrrole (PPy) [87][88][89][90] and polyaniline (PANI). 91,92 In this part, we discuss and analyze the molecular structure design of polysulfanes with carbon chains as the main chains by different methods.…”

High-Performance Cathode Materials for Lithium–Sulfur Batteries Based on Sulfurated Poly(norbornadiene) and Sulfurated Poly(dicyclopentadiene)

“…In order to carry out a practical and simple synthesis process, other strategies that virtually shut down the polysulfide shuttle have been developed. These comprise the use of sulfur-containing polymers such as sulfurized poly­(acrylonitrile) (SPAN) or carbyne polysulfides, ,− ,,− which deliver fairly good capacity and good capacity retention due to the formation of short-chain polysulfides and true solid-phase transition. Applications of SPAN are also beyond Li–S batteries; thus, it has been applied in magnesium–sulfur batteries, sodium–sulfur batteries, and even as a potential anode material for lithium-ion batteries .…”

Sulfurized Polypropylene as Low‐Cost Cathode Material for High‐Capacity Lithium‐Sulfur Batteries

“…[7] A second approach comprises the synthesis of cathode materials with sole solid phase conversion, which directly avoids the polysulfide shuttle. [18,19] Representative compounds are sulfurized poly(acrylonitrile) (SPAN), [20][21][22][23][24][25] or sulfurized carbyne, [26] alucone-coated CÀ S electrodes [27] and graphdiyne-like porous organic frameworks. [28] Cathode materials in this category provide high specific discharge capacity and stable performance owing to the absence of the polysulfideshuttle.…”

“…However, one major drawback of these materials is the low sulfur loading. SPAN has a sulfur loading lower than 45 wt %, [21][22][23][24][25] while the graphdiyne-like porous organic frameworks have sulfur loadings up to 56.8 wt%, [28] which is the highest for cathode materials with sole solid phase transformation. Herein, we report a sulfur-containing polymeric cathode material with sulfur loadings up to 68 wt% that can be used in polysulfideshuttle free LiÀ S batteries, namely sulfurized polypropylene (S/ PP-500), which is prepared via a facile one-step reaction of S 8 with polypropylene (PP) at 500 °C.…”