Effect of binders on the microstructural and electrochemical performance of high‐sulphur‐loading electrodes in lithium‐sulphur batteries

Abstract

Summary Construction of a high‐sulphur‐loading electrode is an effective approach for achieving a high‐specific energy density in lithium‐sulphur batteries. The polymer binder has an important influence on the microstructural and electrochemical behaviours of high‐sulphur‐loading electrodes. In the study, three commonly used binders, namely polyvinylidene fluoride (PVDF), polyacrylonitrile (LA133), and polyacrylic acid (PAA), were used with high‐sulphur‐loading electrodes, and their electrochemical performance characteristics were investigated. The water‐soluble binders LA133 and PAA showed significantly better performance than PVDF. The PAA binder effectively decreased the overpotential polarisation and resistance, increasing the lithium‐ion diffusion coefficient and accelerating the redox reaction of polysulphides. The CNTs@S electrode with PAA as the binder showed the first discharge specific capacity of 703 mAh g−1 at a sulphur loading of 5.1 mg cm−2 at 0.3 C, with a decay rate of 0.1% over 150 cycles. Even with a higher sulphur loading of 7.1 mg cm−2, the electrode exhibited an initial capacity of 6.3 mAh cm−2 at a current density of 1.19 mA cm−2 and capacity retention of 98.4% over 50 cycles. In addition, the electrode with the PAA binder showed significantly increased volume energy density. The aqueous PAA binder is more suitable for the fabrication of high‐sulphur‐loading electrodes for lithium‐sulphur batteries.

Dual Network Electrode Binder toward Practical Lithium–Sulfur Battery Applications

“…Here, water-soluble HA was chosen to mimic the fascia of skeletal muscle due to its abundant polar groups (e.g., −COOH and −OH) with high affinity to LiPS, as well as high adhesion . Meanwhile, oleophilic PCP was designed to function in the role similar to the myofilament of skeletal muscle based on the three following considerations: (1) Polyacrylonitrile (PAN) was reported to be a good oleophilic polymer binder for S-based electrodes by virtue of its good LiPSs-trapping ability . (2) For constructing ionic bonding with HA in order to coordinate deformation and stress output among dual networks, Lewis basic tetrazole motifs were constructed via copolymerizing PAN with poly­(ethylene glycol) bisazide (N 3 –PEO–N 3 ) .…”

“…18 Meanwhile, oleophilic PCP was designed to function in the role similar to the myofilament of skeletal muscle based on the three following considerations: (1) Polyacrylonitrile (PAN) was reported to be a good oleophilic polymer binder for S-based electrodes by virtue of its good LiPSs-trapping ability. 24 (2) For constructing ionic bonding with HA in order to coordinate deformation and stress output among dual networks, Lewis basic tetrazole motifs were constructed via copolymerizing PAN with poly(ethylene glycol) bisazide (N 3 −PEO−N 3 ). 25 (3) The PAN and PEO segments in PCP show high affinity to electrolyte and thus help to construct a high-efficiency ionic transport network within S-based electrodes.…”

N/P Codoped Carbon Nanofibers Coupled with Chrysanthemum-Like Cobalt Phosphide Hybrid for Stable Lithium–Sulfur Batteries

“…7,8 The conventional multiphase transformation in the sulfur cathode also leads to various issues such as slow redox reactions, diminished Coulombic efficiency, and rapid capacity degradation. 9,10 The various approaches being considered to solve these include exploring the possibility of producing a high stability and conductivity cathode, 11,12 developing electrolyte engineering, 13 utilizing functional interlayers or separators, 14−18 and safeguarding the lithium anode. 19 Various carbonaceous materials, such as one-dimensional (1D) (carbon nanofibers/ nanotubes) 20,21 and two-dimensional (2D) (graphene) carbon nanomaterials 22 have been developed during the last few decades because of their excellent electronic conductivity.…”