Binder Engineering Unlocks Stable Sulfurized Polyacrylonitrile Electrodes for Li-ion-Sulfur Cells with layered LiNi1/3Mn1/3Co1/3O2 cathode

Abstract

Li-sulfur (Li-S) batteries are considered highly promising next-generation energy storage systems because of their exceptionally high theoretical energy density (2500-2600 Wh kg–1). However, their practical application is significantly limited by Li-dendrite formation, parasitic side reactions at the Li-metal anode, and the inherent instability of sulfur cathodes. Sulfurized polyacrylonitrile (SPAN) has gained considerable attention as a sulfur host due to its polysulfide-free redox mechanism, which effectively mitigates the shuttle effect. In this study, the electrochemical performance of SPAN electrodes is systematically enhanced by examining the impact of various binders in a conventional electrolyte (1 M LiPF6 in EC/DEC with 5 wt.% LiBOB) using Li-metal half-cells. Amongst, the water-based polyacrylic acid (PAA) binder demonstrates the best performance, delivering a high initial specific capacity of 1438 mAh g–1 and achieving 97% capacity retention after 200 cycles. Moreover, a full-cell configuration is assembled by coupling the optimized SPAN electrode with a commercial layered LiNi1/3Mn1/3Co1/3O2 (NMC111) cathode. The assembled full cell provides an initial capacity of 1155 mAh g–1 and maintains 88% of its capacity after 100 cycles at a current density of 0.5 A g–1 under ambient conditions. Overall, this work demonstrates that binder engineering is an effective approach to fully exploit the potential of SPAN electrodes for practical high-energy Li-based batteries.