Ether-compatible sulfurized polyacrylonitrile cathode with excellent performance enabled by fast kinetics via selenium doping

Abstract

Sulfurized polyacrylonitrile is suggested to contain S n ( n ≤ 4) and shows good electrochemical performance in carbonate electrolytes for lithium sulfur batteries. However inferior results in ether electrolytes suggest that high solubility of Li 2 S n ( n ≤ 4) trumps the limited redox conversion, leading to dissolution and shuttling. Here, we introduce a small amount of selenium in sulfurized polyacrylonitrile to accelerate the redox conversion, delivering excellent performance in both carbonate and ether electrolytes, including high reversible capacity (1300 mA h g −1 at 0.2 A g −1 ), 84% active material utilization and high rate (capacity up to 900 mA h g −1 at 10 A g −1 ). These cathodes can undergo 800 cycles with nearly 100% Coulombic efficiency and ultralow 0.029% capacity decay per cycle. Polysulfide dissolution is successfully suppressed by enhanced reaction kinetics. This work demonstrates an ether compatible sulfur cathode involving intermediate Li 2 S n ( n ≤ 4), attractive rate and cycling performance, and a promising solution towards applicable lithium-sulfur batteries.

Solid‐State Lithium–Sulfur Battery Enabled by Thio‐LiSICON/Polymer Composite Electrolyte and Sulfurized Polyacrylonitrile Cathode

“…Figure 5d displays the charge/discharge profiles of the S/PAN|LCE|Li cell at different C rates (the second cycle of 0.1 C is presented). Reversible capacities of 1183, 719, and 482 mAh g −1 could be achieved at 0.2, 0.5, and 1 C, respectively, revealing a good rate performance of the SSLSB fabricated with S/PAN and LCE electrolytes, which indicate rapid kinetics of S/PAN cathode with Li‐ions 54,55…”

Prospect of Sulfurized Pyrolyzed Poly(acrylonitrile) (S@pPAN) Cathode Materials for Rechargeable Lithium Batteries

“…They further confirmed that the control step of the rate capacity is the activation process of Li 2 S. Recently, Xie et al. introduced small amount of selenium (Se) to alter the structure of S@pPAN composite . It delivered excellent performance, both in ester and ether electrolytes.…”

“…Only 5 mol % Se doping tremendously improved the electronic conduction and reaction kinetics via molecular‐scale dispersion and Se−S bonds. More impressively, Xie confirmed that introduction of a small amount of Se improved capacity retention in ether‐based electrolytes as a result of accelerated redox conversion . Similarly, Se and tellurium (Te) were investigated as eutectic accelerators to enhance the reaction kinetics of S@pPAN composites for room temperature Na–S batteries .…”

Accurate Control Multiple Active Sites of Carbonaceous Anode for High Performance Sodium Storage: Insights into Capacitive Contribution Mechanism

“…Such one step cationic hypercrosslinked strategy has achieved an ideal phase transformation processes from initial 0D micromolecule monomer to final 3D HCPs. Furthermore, the Fourier‐transform infrared spectroscopy (FT‐IR) is performed to analyze the specific bonding formings of both HCPs (Figure S1a, Supporting Information) and derived target microporous carbon (Figure S1b, Supporting Information), and the characteristic peak assignments are summarized in Table S1 in the Supporting Information . Figure b and Figure S2a,b in the Supporting Information exhibit the scanning electron microscopy (SEM) images of HCP‐Py 0.2 Th 0.8 , HCP‐Py, and HCP‐Th, respectively.…”