Synergizing Polysulfide Trapping and Fast Ion Kinetics Enabled by Poly(Acrylamide-co-Lithium Acrylate) Aqueous Binder...

Although lithium-sulfur (Li-S) batteries offer high theoretical energy density, their practical implementation is impeded by the polysulfide shuttle effect and mechanical disintegration of sulfur cathodes, particularly under high-sulfur-loading conditions. To overcome these limitations, a multifunctional aqueous binder, poly(acrylamide-co-lithium acrylate) (AmLA), is proposed to synergistically enhance electrode integrity and suppress lithium polysulfide (LiPS) migration. The copolymer architecture integrates polar amide and lithium carboxylate groups, which establish a robust hydrogen-bonding network for mechanical stability while simultaneously providing strong chemical anchoring sites for LiPS confinement. In situ UV-visible spectroscopy corroborates the significant retardation of LiPS dissolution, confirming the suppression of shuttle reactions. Consequently, AmLA-based sulfur cathodes exhibit superior electrochemical kinetics, delivering a 3.4-fold enhancement in rate capability at 2 C compared to the polyvinylidene fluoride binder. With a high sulfur content of 75 wt% and an areal loading of 3.2 mg cm^-2, the cathode retains a high reversible capacity of 777 mAh g^-1 after 200 cycles, accompanied by reduced polarization. Furthermore, stable cycling is preserved even at a high sulfur loading of 6 mg cm^-2 (7 mAh cm^-2). Thus, AmLA offers a viable strategy for resolving the chemical and mechanical bottlenecks of high-energy-density Li-S batteries.